diff --git a/eslint.config.mjs b/eslint.config.mjs
index 9081ccfe2d..62b0fc99bf 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -502,11 +502,30 @@ export default [
       // certain TypeScript compilation errors after fixes
       '@typescript-eslint/no-unnecessary-type-assertion': 'off',
 
+      '@typescript-eslint/no-inferrable-types': 'error',
+
       '@typescript-eslint/consistent-generic-constructors': [
         'error',
         'constructor',
       ],
 
+      // This is more performant
+      // And should provide better stack trace when debugging
+      // see https://v8.dev/blog/fast-async.
+      '@typescript-eslint/return-await': ['error', 'always'],
+
+      '@typescript-eslint/ban-ts-comment': [
+        'error',
+        {
+          // Change after we add some placeholder for old errors
+          minimumDescriptionLength: 0,
+          'ts-check': false,
+          'ts-expect-error': 'allow-with-description',
+          'ts-ignore': true,
+          'ts-nocheck': true,
+        },
+      ],
+
       'rulesdir/no-underscored-properties': 'error',
       'rulesdir/inline-type-imports': 'error',
 
diff --git a/extensions/cxx_debugging/src/CustomFormatters.ts b/extensions/cxx_debugging/src/CustomFormatters.ts
index d1d3285f7f..2cb5a87c6d 100644
--- a/extensions/cxx_debugging/src/CustomFormatters.ts
+++ b/extensions/cxx_debugging/src/CustomFormatters.ts
@@ -361,7 +361,8 @@ export class CXXValue implements Value, LazyObject {
 
       try {
         const formattedValue = await formatter.format(this.wasm, value);
-        return lazyObjectFromAny(formattedValue, this.objectStore, this.type, this.displayValue, this.memoryAddress)
+        return await lazyObjectFromAny(
+                   formattedValue, this.objectStore, this.type, this.displayValue, this.memoryAddress)
             .asRemoteObject();
       } catch {
         // Fallthrough
@@ -505,7 +506,7 @@ function lazyObjectFromAny(
 }
 
 export class LazyObjectStore {
-  private nextObjectId: number = 0;
+  private nextObjectId = 0;
   private objects = new Map<string, LazyObject>();
 
   store(lazyObject: LazyObject): string {
diff --git a/extensions/cxx_debugging/src/DWARFSymbols.ts b/extensions/cxx_debugging/src/DWARFSymbols.ts
index 46d3f5d403..86070a14d3 100644
--- a/extensions/cxx_debugging/src/DWARFSymbols.ts
+++ b/extensions/cxx_debugging/src/DWARFSymbols.ts
@@ -201,7 +201,7 @@ export class DWARFLanguageExtensionPlugin implements Chrome.DevTools.LanguageExt
           // Ensure directory exists
           if (parentDirectory.length > 1) {
             // TypeScript doesn't know about createPath
-            // @ts-ignore
+            // @ts-expect-error
             backend.FS.createPath('/', parentDirectory.substring(1), true, true);
           }
 
@@ -216,7 +216,7 @@ export class DWARFLanguageExtensionPlugin implements Chrome.DevTools.LanguageExt
               void this.hostInterface.reportResourceLoad(dwoURL, {success: false, errorMessage: (e as Error).message});
               // Rethrow any error fetching the content as errno 44 (EEXIST)
               // TypeScript doesn't know about the ErrnoError constructor
-              // @ts-ignore
+              // @ts-expect-error
               throw new backend.FS.ErrnoError(44);
             }
           };
@@ -557,7 +557,7 @@ export class DWARFLanguageExtensionPlugin implements Chrome.DevTools.LanguageExt
         description: '<optimized out>',
       };
     }
-    return cxxObject.asRemoteObject();
+    return await cxxObject.asRemoteObject();
   }
 
   async getProperties(objectId: Chrome.DevTools.RemoteObjectId): Promise<Chrome.DevTools.PropertyDescriptor[]> {
@@ -582,7 +582,7 @@ export class DWARFLanguageExtensionPlugin implements Chrome.DevTools.LanguageExt
 export async function createPlugin(
     hostInterface: HostInterface, resourceLoader: ResourceLoader,
     moduleConfigurations: ModuleConfigurations = DEFAULT_MODULE_CONFIGURATIONS,
-    logPluginApiCalls: boolean = false): Promise<DWARFLanguageExtensionPlugin> {
+    logPluginApiCalls = false): Promise<DWARFLanguageExtensionPlugin> {
   const plugin = new DWARFLanguageExtensionPlugin(moduleConfigurations, resourceLoader, hostInterface);
   if (logPluginApiCalls) {
     const pluginLoggingProxy = {
diff --git a/extensions/cxx_debugging/src/DevToolsPluginHost.ts b/extensions/cxx_debugging/src/DevToolsPluginHost.ts
index d50ac08b97..c5025c26b2 100644
--- a/extensions/cxx_debugging/src/DevToolsPluginHost.ts
+++ b/extensions/cxx_debugging/src/DevToolsPluginHost.ts
@@ -35,7 +35,7 @@ export class WorkerPlugin implements Chrome.DevTools.LanguageExtensionPlugin, As
 
   static async create(
       moduleConfigurations: ModuleConfigurations = DEFAULT_MODULE_CONFIGURATIONS,
-      logPluginApiCalls: boolean = false): Promise<WorkerPlugin> {
+      logPluginApiCalls = false): Promise<WorkerPlugin> {
     const plugin = new WorkerPlugin();
     await plugin.rpc.sendMessage('hello', moduleConfigurations, logPluginApiCalls);
     return plugin;
diff --git a/extensions/cxx_debugging/tests/RealBackend.ts b/extensions/cxx_debugging/tests/RealBackend.ts
index addcb1371e..b9c380a1ec 100644
--- a/extensions/cxx_debugging/tests/RealBackend.ts
+++ b/extensions/cxx_debugging/tests/RealBackend.ts
@@ -36,7 +36,7 @@ async function waitFor<ReturnT>(
       reject(e);
     }
   };
-  return new Promise<ReturnT>((resolve, reject) => callback(resolve, reject));
+  return await new Promise<ReturnT>((resolve, reject) => callback(resolve, reject));
 }
 
 export interface BreakLocation {
@@ -218,7 +218,7 @@ export class Debugger {
   }
 
   async waitForScript(url: string, timeout = 0): Promise<string> {
-    return waitFor(() => this.scripts.get(url)?.scriptId, timeout);
+    return await waitFor(() => this.scripts.get(url)?.scriptId, timeout);
   }
 
   async waitForPause(timeout = 0): Promise<PauseLocation> {
@@ -227,10 +227,10 @@ export class Debugger {
     }
     const waitPromise = new Promise<PauseLocation>(resolve => this.waitForPauseQueue.push({resolve}));
     if (timeout === 0) {
-      return waitPromise;
+      return await waitPromise;
     }
     const timeoutPromise = new Promise<PauseLocation>((_, r) => setTimeout(() => r(new Error('Timeout')), timeout));
-    return Promise.race([waitPromise, timeoutPromise]);
+    return await Promise.race([waitPromise, timeoutPromise]);
   }
 
   async evaluateFunction<T>(expression: string): Promise<T> {
@@ -285,7 +285,7 @@ export class Debugger {
   async evaluateOnCallFrame<T>(
       expectValue: boolean, convert: (result: Protocol.Runtime.RemoteObject) => T, expression: string,
       {callFrameId}: Protocol.Debugger.CallFrame): Promise<T> {
-    return this.evaluateOnCallFrameId(expectValue, convert, expression, callFrameId);
+    return await this.evaluateOnCallFrameId(expectValue, convert, expression, callFrameId);
   }
 
   async evaluateOnCallFrameId<T>(
@@ -301,7 +301,7 @@ export class Debugger {
   }
 
   async waitForFunction<T>(expression: string, timeout = 0): Promise<T> {
-    return waitFor(() => this.evaluateFunction<T>(expression), timeout);
+    return await waitFor(() => this.evaluateFunction<T>(expression), timeout);
   }
 
   page(script: string): WasmBackendPage {
@@ -465,7 +465,7 @@ class WasmBackendPage {
 
   async go(timeout = 0): Promise<number> {
     await this.debug.waitForFunction('window.isReady && window.isReady()', timeout);
-    return this.debug.evaluateFunction<number>('window.go()');
+    return await this.debug.evaluateFunction<number>('window.go()');
   }
 }
 
diff --git a/extensions/cxx_debugging/tests/TestUtils.ts b/extensions/cxx_debugging/tests/TestUtils.ts
index ca00198c82..7588fdce80 100644
--- a/extensions/cxx_debugging/tests/TestUtils.ts
+++ b/extensions/cxx_debugging/tests/TestUtils.ts
@@ -35,7 +35,7 @@ export function makeURL(path: string): string {
 }
 
 export async function createWorkerPlugin(debug?: Debugger): Promise<Chrome.DevTools.LanguageExtensionPlugin> {
-  return WorkerPlugin.create([], true).then(p => {
+  return await WorkerPlugin.create([], true).then(p => {
     if (debug) {
       p.getWasmLinearMemory = debug.getWasmLinearMemory.bind(debug);
       p.getWasmLocal = debug.getWasmLocal.bind(debug);
@@ -116,52 +116,52 @@ export class TestValue implements Value {
   size: number;
   typeNames: string[];
 
-  static fromInt8(value: number, typeName: string = 'int8_t'): TestValue {
+  static fromInt8(value: number, typeName = 'int8_t'): TestValue {
     const content = new DataView(new ArrayBuffer(1));
     content.setInt8(0, value);
     return new TestValue(content, typeName);
   }
-  static fromInt16(value: number, typeName: string = 'int16_t'): TestValue {
+  static fromInt16(value: number, typeName = 'int16_t'): TestValue {
     const content = new DataView(new ArrayBuffer(2));
     content.setInt16(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromInt32(value: number, typeName: string = 'int32_t'): TestValue {
+  static fromInt32(value: number, typeName = 'int32_t'): TestValue {
     const content = new DataView(new ArrayBuffer(4));
     content.setInt32(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromInt64(value: bigint, typeName: string = 'int64_t'): TestValue {
+  static fromInt64(value: bigint, typeName = 'int64_t'): TestValue {
     const content = new DataView(new ArrayBuffer(8));
     content.setBigInt64(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromUint8(value: number, typeName: string = 'uint8_t'): TestValue {
+  static fromUint8(value: number, typeName = 'uint8_t'): TestValue {
     const content = new DataView(new ArrayBuffer(1));
     content.setUint8(0, value);
     return new TestValue(content, typeName);
   }
-  static fromUint16(value: number, typeName: string = 'uint16_t'): TestValue {
+  static fromUint16(value: number, typeName = 'uint16_t'): TestValue {
     const content = new DataView(new ArrayBuffer(2));
     content.setUint16(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromUint32(value: number, typeName: string = 'uint32_t'): TestValue {
+  static fromUint32(value: number, typeName = 'uint32_t'): TestValue {
     const content = new DataView(new ArrayBuffer(4));
     content.setUint32(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromUint64(value: bigint, typeName: string = 'uint64_t'): TestValue {
+  static fromUint64(value: bigint, typeName = 'uint64_t'): TestValue {
     const content = new DataView(new ArrayBuffer(8));
     content.setBigUint64(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromFloat32(value: number, typeName: string = 'float'): TestValue {
+  static fromFloat32(value: number, typeName = 'float'): TestValue {
     const content = new DataView(new ArrayBuffer(4));
     content.setFloat32(0, value, true);
     return new TestValue(content, typeName);
   }
-  static fromFloat64(value: number, typeName: string = 'double'): TestValue {
+  static fromFloat64(value: number, typeName = 'double'): TestValue {
     const content = new DataView(new ArrayBuffer(8));
     content.setFloat64(0, value, true);
     return new TestValue(content, typeName);
diff --git a/front_end/core/common/Color.ts b/front_end/core/common/Color.ts
index 74732cd401..fca46f7f63 100644
--- a/front_end/core/common/Color.ts
+++ b/front_end/core/common/Color.ts
@@ -65,7 +65,7 @@ function normalizeHue(hue: number): number {
 // and returns the canonicalized `degree`.
 function parseAngle(angleText: string): number|null {
   const angle = angleText.replace(/(deg|g?rad|turn)$/, '');
-  // @ts-ignore: isNaN can accept strings
+  // @ts-expect-error: isNaN can accept strings
   if (isNaN(angle) || angleText.match(/\s+(deg|g?rad|turn)/)) {
     return null;
   }
@@ -337,7 +337,7 @@ function parseAlpha(value: string|undefined): number|null {
  * - 20% in range [0, 1] is 0.5
  */
 function parsePercentOrNumber(value: string, range: [number, number] = [0, 1]): number|null {
-  // @ts-ignore: isNaN can accept strings
+  // @ts-expect-error: isNaN can accept strings
   if (isNaN(value.replace('%', ''))) {
     return null;
   }
@@ -366,7 +366,7 @@ function parseRgbNumeric(value: string): number|null {
 
 export function parseHueNumeric(value: string): number|null {
   const angle = value.replace(/(deg|g?rad|turn)$/, '');
-  // @ts-ignore: isNaN can accept strings
+  // @ts-expect-error: isNaN can accept strings
   if (isNaN(angle) || value.match(/\s+(deg|g?rad|turn)/)) {
     return null;
   }
@@ -385,7 +385,7 @@ export function parseHueNumeric(value: string): number|null {
 }
 
 function parseSatLightNumeric(value: string): number|null {
-  // @ts-ignore: isNaN can accept strings
+  // @ts-expect-error: isNaN can accept strings
   if (value.indexOf('%') !== value.length - 1 || isNaN(value.replace('%', ''))) {
     return null;
   }
@@ -762,7 +762,7 @@ export class Lab implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color3D|Color4DOr3D {
+  #getRGBArray(withAlpha = true): Color3D|Color4DOr3D {
     const params = ColorConverter.xyzd50ToSrgb(...this.#toXyzd50());
     if (withAlpha) {
       return [...params, this.alpha ?? undefined];
@@ -899,7 +899,7 @@ export class LCH implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     const params = ColorConverter.xyzd50ToSrgb(...this.#toXyzd50());
     if (withAlpha) {
       return [...params, this.alpha ?? undefined];
@@ -1039,7 +1039,7 @@ export class Oklab implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     const params = ColorConverter.xyzd50ToSrgb(...this.#toXyzd50());
     if (withAlpha) {
       return [...params, this.alpha ?? undefined];
@@ -1176,7 +1176,7 @@ export class Oklch implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     const params = ColorConverter.xyzd50ToSrgb(...this.#toXyzd50());
     if (withAlpha) {
       return [...params, this.alpha ?? undefined];
@@ -1336,7 +1336,7 @@ export class ColorFunction implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     // With color(), out-of-gamut inputs are to be used for intermediate computations
     const [p0, p1, p2] = this.#rawParams;
     const params: Color3D =
@@ -1531,7 +1531,7 @@ export class HSL implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     const rgb = hsl2rgb([this.h, this.s, this.l, 0]);
     if (withAlpha) {
       return [rgb[0], rgb[1], rgb[2], this.alpha ?? undefined];
@@ -1682,7 +1682,7 @@ export class HWB implements Color {
 
   #getRGBArray(withAlpha: true): Color4DOr3D;
   #getRGBArray(withAlpha: false): Color3D;
-  #getRGBArray(withAlpha: boolean = true): Color4DOr3D|Color3D {
+  #getRGBArray(withAlpha = true): Color4DOr3D|Color3D {
     const rgb = hwb2rgb([this.h, this.w, this.b, 0]);
     if (withAlpha) {
       return [rgb[0], rgb[1], rgb[2], this.alpha ?? undefined];
@@ -2200,9 +2200,9 @@ export class Legacy implements Color {
   }
 }
 
-export const Regex: RegExp =
+export const Regex =
     /((?:rgba?|hsla?|hwba?|lab|lch|oklab|oklch|color)\([^)]+\)|#[0-9a-fA-F]{8}|#[0-9a-fA-F]{6}|#[0-9a-fA-F]{3,4}|\b[a-zA-Z]+\b(?!-))/g;
-export const ColorMixRegex: RegExp = /color-mix\(.*,\s*(?<firstColor>.+)\s*,\s*(?<secondColor>.+)\s*\)/g;
+export const ColorMixRegex = /color-mix\(.*,\s*(?<firstColor>.+)\s*,\s*(?<secondColor>.+)\s*\)/g;
 
 const COLOR_TO_RGBA_ENTRIES: Array<readonly[string, number[]]> = [
   ['aliceblue', [240, 248, 255]],
diff --git a/front_end/core/common/ColorConverter.ts b/front_end/core/common/ColorConverter.ts
index 2a8367873d..b9d2311e26 100644
--- a/front_end/core/common/ColorConverter.ts
+++ b/front_end/core/common/ColorConverter.ts
@@ -66,7 +66,7 @@ class TransferFunction {
   e: number;
   f: number;
 
-  constructor(g: number, a: number, b: number = 0, c: number = 0, d: number = 0, e: number = 0, f: number = 0) {
+  constructor(g: number, a: number, b = 0, c = 0, d = 0, e = 0, f = 0) {
     this.g = g;
     this.a = a;
     this.b = b;
diff --git a/front_end/core/common/ResolverBase.ts b/front_end/core/common/ResolverBase.ts
index 5ce26de2be..cb0e0b9ad8 100644
--- a/front_end/core/common/ResolverBase.ts
+++ b/front_end/core/common/ResolverBase.ts
@@ -28,7 +28,7 @@ export abstract class ResolverBase<Id, T> {
   async waitFor(id: Id): Promise<T> {
     const obj = this.getForId(id);
     if (!obj) {
-      return this.getOrCreatePromise(id);
+      return await this.getOrCreatePromise(id);
     }
     return obj;
   }
diff --git a/front_end/core/common/Revealer.ts b/front_end/core/common/Revealer.ts
index 53528dcbc4..96eb3e0d92 100644
--- a/front_end/core/common/Revealer.ts
+++ b/front_end/core/common/Revealer.ts
@@ -164,7 +164,7 @@ export function registerRevealer<T>(registration: RevealerRegistration<T>): void
  * @param revealable the object to reveal.
  * @param omitFocus whether to omit focusing on the presentation of `revealable` afterwards.
  */
-export async function reveal(revealable: unknown, omitFocus: boolean = false): Promise<void> {
+export async function reveal(revealable: unknown, omitFocus = false): Promise<void> {
   await RevealerRegistry.instance().reveal(revealable, omitFocus);
 }
 
diff --git a/front_end/core/common/SettingRegistration.ts b/front_end/core/common/SettingRegistration.ts
index fc17d6fcbf..de38248b87 100644
--- a/front_end/core/common/SettingRegistration.ts
+++ b/front_end/core/common/SettingRegistration.ts
@@ -97,7 +97,7 @@ export function getRegisteredSettings(): SettingRegistration[] {
   return registeredSettings.filter(setting => Root.Runtime.Runtime.isDescriptorEnabled(setting));
 }
 
-export function registerSettingsForTest(settings: SettingRegistration[], forceReset: boolean = false): void {
+export function registerSettingsForTest(settings: SettingRegistration[], forceReset = false): void {
   if (registeredSettings.length === 0 || forceReset) {
     registeredSettings = settings;
     settingNameSet.clear();
diff --git a/front_end/core/common/Settings.ts b/front_end/core/common/Settings.ts
index aa1408d463..d0bcd40304 100644
--- a/front_end/core/common/Settings.ts
+++ b/front_end/core/common/Settings.ts
@@ -256,7 +256,7 @@ export const NOOP_STORAGE: SettingsBackingStore = {
 export class SettingsStorage {
   constructor(
       private object: Record<string, string>, private readonly backingStore: SettingsBackingStore = NOOP_STORAGE,
-      private readonly storagePrefix: string = '') {
+      private readonly storagePrefix = '') {
   }
 
   register(name: string): void {
@@ -690,11 +690,11 @@ export class VersionController {
         Math.min(this.#globalVersionSetting.get(), this.#syncedVersionSetting.get(), this.#localVersionSetting.get());
     const methodsToRun = this.methodsToRunToUpdateVersion(minimumVersion, currentVersion);
     console.assert(
-        // @ts-ignore
+        // @ts-expect-error
         this[`updateVersionFrom${currentVersion}To${currentVersion + 1}`] === undefined,
         'Unexpected migration method found. Increment CURRENT_VERSION or remove the method.');
     for (const method of methodsToRun) {
-      // @ts-ignore Special version method matching
+      // @ts-expect-error Special version method matching
       this[method].call(this);
     }
     this.resetToCurrent();
diff --git a/front_end/core/dom_extension/DOMExtension.ts b/front_end/core/dom_extension/DOMExtension.ts
index 5060011dba..eccfb7f374 100644
--- a/front_end/core/dom_extension/DOMExtension.ts
+++ b/front_end/core/dom_extension/DOMExtension.ts
@@ -34,6 +34,7 @@
  * http://ejohn.org/files/jsdiff.js (released under the MIT license).
  */
 
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
 // @ts-nocheck This file is not checked by TypeScript Compiler as it has a lot of legacy code.
 
 import * as Platform from '../platform/platform.js';
@@ -290,7 +291,7 @@ Node.prototype.isSelfOrDescendant = function(node: Node|null): boolean {
   return Boolean(node) && (node === this || this.isDescendant(node));
 };
 
-Node.prototype.traverseNextNode = function(stayWithin?: Node, skipShadowRoot: boolean = false): Node|null {
+Node.prototype.traverseNextNode = function(stayWithin?: Node, skipShadowRoot = false): Node|null {
   if (!skipShadowRoot && this.shadowRoot) {
     return this.shadowRoot;
   }
diff --git a/front_end/core/host/InspectorFrontendHost.ts b/front_end/core/host/InspectorFrontendHost.ts
index 0ca98788aa..518530ffda 100644
--- a/front_end/core/host/InspectorFrontendHost.ts
+++ b/front_end/core/host/InspectorFrontendHost.ts
@@ -406,7 +406,7 @@ export class InspectorFrontendHostStub implements InspectorFrontendHostAPI {
 
   getSyncInformation(callback: (arg0: SyncInformation) => void): void {
     if ('getSyncInformationForTesting' in globalThis) {
-      // @ts-ignore for testing
+      // @ts-expect-error for testing
       return callback(globalThis.getSyncInformationForTesting());
     }
     callback({
@@ -554,14 +554,14 @@ export class InspectorFrontendHostStub implements InspectorFrontendHostAPI {
   }
 }
 
-// @ts-ignore Global injected by devtools_compatibility.js
+// @ts-expect-error Global injected by devtools_compatibility.js
 // eslint-disable-next-line @typescript-eslint/naming-convention
 export let InspectorFrontendHostInstance: InspectorFrontendHostStub = globalThis.InspectorFrontendHost;
 
 class InspectorFrontendAPIImpl {
   constructor() {
     for (const descriptor of EventDescriptors) {
-      // @ts-ignore Dispatcher magic
+      // @ts-expect-error Dispatcher magic
       this[descriptor[1]] = this.dispatch.bind(this, descriptor[0], descriptor[2], descriptor[3]);
     }
   }
@@ -602,7 +602,7 @@ function initializeInspectorFrontendHost(): void {
   let proto;
   if (!InspectorFrontendHostInstance) {
     // Instantiate stub for web-hosted mode if necessary.
-    // @ts-ignore Global injected by devtools_compatibility.js
+    // @ts-expect-error Global injected by devtools_compatibility.js
     globalThis.InspectorFrontendHost = InspectorFrontendHostInstance = new InspectorFrontendHostStub();
   } else {
     // Otherwise add stubs for missing methods that are declared in the interface.
@@ -611,13 +611,13 @@ function initializeInspectorFrontendHost(): void {
       // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
       // @ts-expect-error
       const stub = proto[name];
-      // @ts-ignore Global injected by devtools_compatibility.js
+      // @ts-expect-error Global injected by devtools_compatibility.js
       if (typeof stub !== 'function' || InspectorFrontendHostInstance[name]) {
         continue;
       }
 
       console.error(`Incompatible embedder: method Host.InspectorFrontendHost.${name} is missing. Using stub instead.`);
-      // @ts-ignore Global injected by devtools_compatibility.js
+      // @ts-expect-error Global injected by devtools_compatibility.js
       InspectorFrontendHostInstance[name] = stub;
     }
   }
@@ -629,7 +629,7 @@ function initializeInspectorFrontendHost(): void {
 // FIXME: This file is included into both apps, since the devtools_app needs the InspectorFrontendHostAPI only,
 // so the host instance should not be initialized there.
 initializeInspectorFrontendHost();
-// @ts-ignore Global injected by devtools_compatibility.js
+// @ts-expect-error Global injected by devtools_compatibility.js
 globalThis.InspectorFrontendAPI = new InspectorFrontendAPIImpl();
 })();
 
diff --git a/front_end/core/platform/MimeType.ts b/front_end/core/platform/MimeType.ts
index 14c4e05c3a..f65aa6b1a2 100644
--- a/front_end/core/platform/MimeType.ts
+++ b/front_end/core/platform/MimeType.ts
@@ -148,7 +148,7 @@ function parseMimeType(contentType: string): {mimeType: string|null, params: Map
  * @returns the smallest index of any character in 'characters' or -1 if none of
  * the characters occur in 'searchString'
  */
-function findFirstIndexOf(searchString: string, characters: string, pos: number = 0): number {
+function findFirstIndexOf(searchString: string, characters: string, pos = 0): number {
   for (let i = pos; i < searchString.length; i++) {
     if (characters.includes(searchString[i])) {
       return i;
@@ -161,7 +161,7 @@ function findFirstIndexOf(searchString: string, characters: string, pos: number
  * @returns the smallest index of any character not in 'characters' or -1 if only
  * 'characters' occur in 'searchString'
  */
-function findFirstIndexNotOf(searchString: string, characters: string, pos: number = 0): number {
+function findFirstIndexNotOf(searchString: string, characters: string, pos = 0): number {
   for (let i = pos; i < searchString.length; i++) {
     if (!characters.includes(searchString[i])) {
       return i;
diff --git a/front_end/core/platform/NumberUtilities.ts b/front_end/core/platform/NumberUtilities.ts
index ba5ed894f9..c16f3ca12a 100644
--- a/front_end/core/platform/NumberUtilities.ts
+++ b/front_end/core/platform/NumberUtilities.ts
@@ -27,7 +27,7 @@ export const toFixedIfFloating = (value: string): string => {
 /**
  * Rounds a number (including float) down.
  */
-export const floor = (value: number, precision: number = 0): number => {
+export const floor = (value: number, precision = 0): number => {
   // Allows for rounding to the nearest whole number.
   // Ex: 1 / 10 -> round down to nearest 10th place
   // Ex: 1 / 5 -> round down to nearest 5
diff --git a/front_end/core/platform/StringUtilities.ts b/front_end/core/platform/StringUtilities.ts
index f4c94e2a5f..c7ddf05471 100644
--- a/front_end/core/platform/StringUtilities.ts
+++ b/front_end/core/platform/StringUtilities.ts
@@ -52,7 +52,7 @@ export const formatAsJSLiteral = (content: string): string => {
   const escapePattern = (match: string, pattern: string, controlChar: string, loneSurrogate: string): string => {
     if (controlChar) {
       if (escapedReplacements.has(controlChar)) {
-        // @ts-ignore https://github.com/microsoft/TypeScript/issues/13086
+        // @ts-expect-error https://github.com/microsoft/TypeScript/issues/13086
         return escapedReplacements.get(controlChar);
       }
       const twoDigitHex = toHexadecimal(controlChar.charCodeAt(0), 2);
@@ -292,7 +292,7 @@ export const filterRegex = function(query: string): RegExp {
 };
 
 export const createSearchRegex = function(
-    query: string, caseSensitive: boolean, isRegex: boolean, matchWholeWord: boolean = false): RegExp {
+    query: string, caseSensitive: boolean, isRegex: boolean, matchWholeWord = false): RegExp {
   const regexFlags = caseSensitive ? 'g' : 'gi';
   let regexObject;
 
diff --git a/front_end/core/protocol_client/InspectorBackend.ts b/front_end/core/protocol_client/InspectorBackend.ts
index bc9f4441cc..ea3d37affe 100644
--- a/front_end/core/protocol_client/InspectorBackend.ts
+++ b/front_end/core/protocol_client/InspectorBackend.ts
@@ -101,7 +101,7 @@ interface CallbackWithDebugInfo {
 
 export class InspectorBackend {
   readonly agentPrototypes = new Map<ProtocolDomainName, AgentPrototype>();
-  #initialized: boolean = false;
+  #initialized = false;
   #eventParameterNamesForDomain = new Map<ProtocolDomainName, EventParameterNames>();
   readonly typeMap = new Map<QualifiedName, CommandParameter[]>();
   readonly enumMap = new Map<QualifiedName, Record<string, string>>();
@@ -153,13 +153,13 @@ export class InspectorBackend {
 
   registerEnum(type: QualifiedName, values: Record<string, string>): void {
     const [domain, name] = splitQualifiedName(type);
-    // @ts-ignore globalThis global namespace pollution
+    // @ts-expect-error globalThis global namespace pollution
     if (!globalThis.Protocol[domain]) {
-      // @ts-ignore globalThis global namespace pollution
+      // @ts-expect-error globalThis global namespace pollution
       globalThis.Protocol[domain] = {};
     }
 
-    // @ts-ignore globalThis global namespace pollution
+    // @ts-expect-error globalThis global namespace pollution
     globalThis.Protocol[domain][name] = values;
     this.enumMap.set(type, values);
     this.#initialized = true;
@@ -947,7 +947,7 @@ class AgentPrototype {
     function sendMessagePromise(this: AgentPrototype, ...args: unknown[]): Promise<unknown> {
       return AgentPrototype.prototype.sendMessageToBackendPromise.call(this, domainAndMethod, parameters, args);
     }
-    // @ts-ignore Method code generation
+    // @ts-expect-error Method code generation
     this[methodName] = sendMessagePromise;
     this.metadata[domainAndMethod] = {parameters, description, replyArgs};
 
@@ -955,7 +955,7 @@ class AgentPrototype {
       return this.invoke(domainAndMethod, request);
     }
 
-    // @ts-ignore Method code generation
+    // @ts-expect-error Method code generation
     this['invoke_' + methodName] = invoke;
     this.replyArgs[domainAndMethod] = replyArgs;
   }
@@ -1107,7 +1107,7 @@ class DispatcherManager<Domain extends ProtocolDomainName> {
 
       if (event in dispatcher) {
         const f = dispatcher[event as string as keyof ProtocolProxyApi.ProtocolDispatchers[Domain]];
-        // @ts-ignore Can't type check the dispatch.
+        // @ts-expect-error Can't type check the dispatch.
         f.call(dispatcher, messageParams);
       }
     }
diff --git a/front_end/core/protocol_client/protocol_client.ts b/front_end/core/protocol_client/protocol_client.ts
index 6f4b3f92db..ccc94969a9 100644
--- a/front_end/core/protocol_client/protocol_client.ts
+++ b/front_end/core/protocol_client/protocol_client.ts
@@ -14,7 +14,7 @@ export {
 
 // Create the global here because registering commands will involve putting
 // items onto the global.
-// @ts-ignore Global namespace instantiation
+// @ts-expect-error Global namespace instantiation
 self.Protocol = self.Protocol || {};
 
 // FIXME: This instance of InspectorBackend should not be a side effect of importing this module.
diff --git a/front_end/core/sdk/AnimationModel.ts b/front_end/core/sdk/AnimationModel.ts
index 71007195cb..7bd3a3201d 100644
--- a/front_end/core/sdk/AnimationModel.ts
+++ b/front_end/core/sdk/AnimationModel.ts
@@ -57,7 +57,7 @@ export class AnimationDOMNode {
   #scrollListenersById: Map<number, ScrollListener>;
   #scrollBindingListener?: BindingListener;
 
-  static lastAddedListenerId: number = 0;
+  static lastAddedListenerId = 0;
 
   constructor(domNode: DOMNode) {
     this.#domNode = domNode;
@@ -138,14 +138,14 @@ export class AnimationDOMNode {
       }
 
       const scrollingElement = ('scrollingElement' in this ? this.scrollingElement : this) as HTMLElement;
-      // @ts-ignore We're setting a custom field on `Element` or `Document` for retaining the function on the page.
+      // @ts-expect-error We're setting a custom field on `Element` or `Document` for retaining the function on the page.
       this[scrollListenerNameInPage] = () => {
-        // @ts-ignore `reportScrollPosition` binding is injected to the page before calling the function.
+        // @ts-expect-error `reportScrollPosition` binding is injected to the page before calling the function.
         globalThis[reportScrollPositionBindingName](
             JSON.stringify({scrollTop: scrollingElement.scrollTop, scrollLeft: scrollingElement.scrollLeft, id}));
       };
 
-      // @ts-ignore We've already defined the function used below.
+      // @ts-expect-error We've already defined the function used below.
       this.addEventListener('scroll', this[scrollListenerNameInPage], true);
     }
   }
@@ -168,15 +168,15 @@ export class AnimationDOMNode {
     }
 
     function removeScrollListenerInPage(this: HTMLElement|Document, scrollListenerNameInPage: string): void {
-      // @ts-ignore We've already set this custom field while adding scroll listener.
+      // @ts-expect-error We've already set this custom field while adding scroll listener.
       this.removeEventListener('scroll', this[scrollListenerNameInPage]);
-      // @ts-ignore We've already set this custom field while adding scroll listener.
+      // @ts-expect-error We've already set this custom field while adding scroll listener.
       delete this[scrollListenerNameInPage];
     }
   }
 
   async scrollTop(): Promise<number|null> {
-    return this.#domNode.callFunction(scrollTopInPage).then(res => res?.value ?? null);
+    return await this.#domNode.callFunction(scrollTopInPage).then(res => res?.value ?? null);
 
     function scrollTopInPage(this: Element|Document): number {
       if ('scrollingElement' in this) {
@@ -191,7 +191,7 @@ export class AnimationDOMNode {
   }
 
   async scrollLeft(): Promise<number|null> {
-    return this.#domNode.callFunction(scrollLeftInPage).then(res => res?.value ?? null);
+    return await this.#domNode.callFunction(scrollLeftInPage).then(res => res?.value ?? null);
 
     function scrollLeftInPage(this: Element|Document): number {
       if ('scrollingElement' in this) {
@@ -238,7 +238,7 @@ export class AnimationDOMNode {
   }
 
   async verticalScrollRange(): Promise<number|null> {
-    return this.#domNode.callFunction(verticalScrollRangeInPage).then(res => res?.value ?? null);
+    return await this.#domNode.callFunction(verticalScrollRangeInPage).then(res => res?.value ?? null);
 
     function verticalScrollRangeInPage(this: Element|Document): number {
       if ('scrollingElement' in this) {
@@ -254,7 +254,7 @@ export class AnimationDOMNode {
   }
 
   async horizontalScrollRange(): Promise<number|null> {
-    return this.#domNode.callFunction(horizontalScrollRangeInPage).then(res => res?.value ?? null);
+    return await this.#domNode.callFunction(horizontalScrollRangeInPage).then(res => res?.value ?? null);
 
     function horizontalScrollRangeInPage(this: Element|Document): number {
       if ('scrollingElement' in this) {
@@ -1065,7 +1065,7 @@ export class ScreenshotCapture {
   readonly #screenCaptureModel: ScreenCaptureModel;
   readonly #animationModel: AnimationModel;
   // This prevents multiple synchronous calls to captureScreenshots to result in one startScreencast call in model.
-  #isCapturing: boolean = false;
+  #isCapturing = false;
   // Holds the id for capturing & cancelling the screencast operation.
   #screencastOperationId: number|undefined;
   #stopTimer?: number;
diff --git a/front_end/core/sdk/CPUThrottlingManager.ts b/front_end/core/sdk/CPUThrottlingManager.ts
index 43383b3376..01af9b7d9c 100644
--- a/front_end/core/sdk/CPUThrottlingManager.ts
+++ b/front_end/core/sdk/CPUThrottlingManager.ts
@@ -128,14 +128,14 @@ export class CPUThrottlingManager extends Common.ObjectWrapper.ObjectWrapper<Eve
     // If the main target hasn't attached yet, block callers until it appears.
     if (!target) {
       if (existingCallback) {
-        return new Promise(r => {
+        return await new Promise(r => {
           this.#pendingMainTargetPromise = (result: number) => {
             r(result);
             existingCallback(result);
           };
         });
       }
-      return new Promise(r => {
+      return await new Promise(r => {
         this.#pendingMainTargetPromise = r;
       });
     }
diff --git a/front_end/core/sdk/CSSMatchedStyles.ts b/front_end/core/sdk/CSSMatchedStyles.ts
index 93383ec5c4..cc65dec604 100644
--- a/front_end/core/sdk/CSSMatchedStyles.ts
+++ b/front_end/core/sdk/CSSMatchedStyles.ts
@@ -815,7 +815,7 @@ class NodeCascade {
   readonly activeProperties = new Map<string, CSSProperty>();
   constructor(
       matchedStyles: CSSMatchedStyles, styles: CSSStyleDeclaration[], isInherited: boolean,
-      isHighlightPseudoCascade: boolean = false) {
+      isHighlightPseudoCascade = false) {
     this.#matchedStyles = matchedStyles;
     this.styles = styles;
     this.#isInherited = isInherited;
diff --git a/front_end/core/sdk/CSSMetadata.ts b/front_end/core/sdk/CSSMetadata.ts
index 5b1bf4cc0f..940fd0c4cd 100644
--- a/front_end/core/sdk/CSSMetadata.ts
+++ b/front_end/core/sdk/CSSMetadata.ts
@@ -367,13 +367,13 @@ export class CSSMetadata {
 // [^- ][a-zA-Z-]+ matches property key values (e.g. smaller, x-large, initial)
 // -?\+?(?:[0-9]+\.[0-9]+|\.[0-9]+|[0-9]+) matches numeric property values (e.g. -.23, 3.3, 55)
 // [a-zA-Z%]{0,4} matches the units of numeric property values (e.g. px, vmin, or blank units)
-export const FontPropertiesRegex: RegExp = /^[^- ][a-zA-Z-]+$|^-?\+?(?:[0-9]+\.[0-9]+|\.[0-9]+|[0-9]+)[a-zA-Z%]{0,4}$/;
+export const FontPropertiesRegex = /^[^- ][a-zA-Z-]+$|^-?\+?(?:[0-9]+\.[0-9]+|\.[0-9]+|[0-9]+)[a-zA-Z%]{0,4}$/;
 
 // "[\w \,-]+",? ? matches double quoted values and the trailing comma/space (e.g. "Tahoma", )
 // ('[\w \,-]+',? ?) matches single quoted values and the trailing comma/space (e.g. 'Segoe UI', )
 // ([\w \,-]+,? ?) matches non quoted values and the trailing comma/space (e.g. Helvetica)
 // (?: ...)+ will match 1 or more of the groups above such that it would match a value with fallbacks (e.g. "Tahoma", 'Segoe UI', Helvetica)
-export const FontFamilyRegex: RegExp = /^("[\w \,-]+"?, ?|'[\w \,-]+',? ?|[\w \-]+,? ?)+$/;
+export const FontFamilyRegex = /^("[\w \,-]+"?, ?|'[\w \,-]+',? ?|[\w \-]+,? ?)+$/;
 
 export const CubicBezierKeywordValues = new Map([
   ['linear', 'cubic-bezier(0, 0, 1, 1)'],
diff --git a/front_end/core/sdk/CSSModel.ts b/front_end/core/sdk/CSSModel.ts
index 3ce2f0e1d1..bbe36bc4cd 100644
--- a/front_end/core/sdk/CSSModel.ts
+++ b/front_end/core/sdk/CSSModel.ts
@@ -398,7 +398,7 @@ export class CSSModel extends SDKModel<EventTypes> {
     if (!this.isEnabled()) {
       await this.enable();
     }
-    return this.#styleLoader.computedStylePromise(nodeId);
+    return await this.#styleLoader.computedStylePromise(nodeId);
   }
 
   async getBackgroundColors(nodeId: Protocol.DOM.NodeId): Promise<ContrastInfo|null> {
@@ -828,7 +828,7 @@ export class CSSModel extends SDKModel<EventTypes> {
   }
 
   override async resumeModel(): Promise<void> {
-    return this.enable();
+    return await this.enable();
   }
 
   setEffectivePropertyValueForNode(nodeId: Protocol.DOM.NodeId, propertyName: string, value: string): void {
diff --git a/front_end/core/sdk/CSSProperty.ts b/front_end/core/sdk/CSSProperty.ts
index 33f04bb809..364b83a8f6 100644
--- a/front_end/core/sdk/CSSProperty.ts
+++ b/front_end/core/sdk/CSSProperty.ts
@@ -255,7 +255,7 @@ export class CSSProperty extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
     const text = new TextUtils.Text.Text(this.ownerStyle.cssText || '');
     const newStyleText = text.replaceRange(range, Platform.StringUtilities.sprintf(';%s;', propertyText));
     const styleText = await CSSProperty.formatStyle(newStyleText, indentation, endIndentation);
-    return this.ownerStyle.setText(styleText, majorChange);
+    return await this.ownerStyle.setText(styleText, majorChange);
   }
 
   static async formatStyle(styleText: string, indentation: string, endIndentation: string): Promise<string> {
@@ -383,7 +383,7 @@ export class CSSProperty extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
     } else {
       text = appendSemicolonIfMissing(this.text.substring(2, propertyText.length - 2).trim());
     }
-    return this.setText(text, true, true);
+    return await this.setText(text, true, true);
   }
 
   /**
diff --git a/front_end/core/sdk/CSSPropertyParser.ts b/front_end/core/sdk/CSSPropertyParser.ts
index 5f9a27b758..b725dbf70c 100644
--- a/front_end/core/sdk/CSSPropertyParser.ts
+++ b/front_end/core/sdk/CSSPropertyParser.ts
@@ -293,7 +293,7 @@ class ComputedTextChunk {
 export class ComputedText {
   readonly #chunks: ComputedTextChunk[] = [];
   readonly text: string;
-  #sorted: boolean = true;
+  #sorted = true;
   constructor(text: string) {
     this.text = text;
   }
diff --git a/front_end/core/sdk/CSSSupports.ts b/front_end/core/sdk/CSSSupports.ts
index 62a838449d..96a7021b41 100644
--- a/front_end/core/sdk/CSSSupports.ts
+++ b/front_end/core/sdk/CSSSupports.ts
@@ -13,7 +13,7 @@ export class CSSSupports extends CSSQuery {
     return payload.map(supports => new CSSSupports(cssModel, supports));
   }
 
-  #active: boolean = true;
+  #active = true;
 
   constructor(cssModel: CSSModel, payload: Protocol.CSS.CSSSupports) {
     super(cssModel);
diff --git a/front_end/core/sdk/ConsoleModel.ts b/front_end/core/sdk/ConsoleModel.ts
index a0f8e6ef96..4175922e47 100644
--- a/front_end/core/sdk/ConsoleModel.ts
+++ b/front_end/core/sdk/ConsoleModel.ts
@@ -485,7 +485,7 @@ export class ConsoleModel extends SDKModel<EventTypes> {
         ++index;
       }
       const name = prefix + index;
-      // @ts-ignore Assignment to global object
+      // @ts-expect-error Assignment to global object
       this[name] = value;
       return name;
     }
@@ -604,7 +604,7 @@ export class ConsoleMessage {
   #exceptionId?: number = undefined;
   #affectedResources?: AffectedResources;
   category?: Protocol.Log.LogEntryCategory;
-  isCookieReportIssue: boolean = false;
+  isCookieReportIssue = false;
 
   /**
    * The parent frame of the `console.log` call of logpoints or conditional breakpoints
diff --git a/front_end/core/sdk/DOMDebuggerModel.ts b/front_end/core/sdk/DOMDebuggerModel.ts
index 9f90a487a3..ba64d2c336 100644
--- a/front_end/core/sdk/DOMDebuggerModel.ts
+++ b/front_end/core/sdk/DOMDebuggerModel.ts
@@ -380,9 +380,9 @@ export class EventListener {
           },
           type: string, listener: () => void, useCapture: boolean): void {
         this.removeEventListener(type, listener, useCapture);
-        // @ts-ignore:
+        // @ts-expect-error:
         if (this['on' + type]) {
-          // @ts-ignore:
+          // @ts-expect-error:
           this['on' + type] = undefined;
         }
       }
diff --git a/front_end/core/sdk/DOMModel.ts b/front_end/core/sdk/DOMModel.ts
index 895244c419..4e64cc7b1f 100644
--- a/front_end/core/sdk/DOMModel.ts
+++ b/front_end/core/sdk/DOMModel.ts
@@ -215,7 +215,7 @@ export class DOMNode {
   private async requestChildDocument(frameId: Protocol.Page.FrameId, notInTarget: Target): Promise<DOMDocument|null> {
     const frame = await FrameManager.instance().getOrWaitForFrame(frameId, notInTarget);
     const childModel = frame.resourceTreeModel()?.target().model(DOMModel);
-    return childModel?.requestDocument() || null;
+    return await (childModel?.requestDocument() || null);
   }
 
   isAdFrameNode(): boolean {
@@ -1565,7 +1565,7 @@ export class DOMModel extends SDKModel<EventTypes> {
         name: string,
         value: string,
       }>,
-      pierce: boolean = false): Promise<Protocol.DOM.NodeId[]> {
+      pierce = false): Promise<Protocol.DOM.NodeId[]> {
     await this.requestDocument();
     if (!this.#document) {
       throw new Error('DOMModel.getNodesByStyle expects to have a document.');
@@ -1836,7 +1836,7 @@ export class DOMModelUndoStack {
 
   async undo(): Promise<void> {
     if (this.#index === 0) {
-      return Promise.resolve();
+      return await Promise.resolve();
     }
     --this.#index;
     this.#lastModelWithMinorChange = null;
@@ -1845,7 +1845,7 @@ export class DOMModelUndoStack {
 
   async redo(): Promise<void> {
     if (this.#index >= this.#stack.length) {
-      return Promise.resolve();
+      return await Promise.resolve();
     }
     ++this.#index;
     this.#lastModelWithMinorChange = null;
diff --git a/front_end/core/sdk/DebuggerModel.ts b/front_end/core/sdk/DebuggerModel.ts
index 70991e65d9..2e95f0df65 100644
--- a/front_end/core/sdk/DebuggerModel.ts
+++ b/front_end/core/sdk/DebuggerModel.ts
@@ -332,7 +332,7 @@ export class DebuggerModel extends SDKModel<EventTypes> {
     const maxScriptsCacheSize = isRemoteFrontend ? 10e6 : 100e6;
     const enablePromise = this.agent.invoke_enable({maxScriptsCacheSize});
     void enablePromise.then(this.registerDebugger.bind(this));
-    return enablePromise;
+    return await enablePromise;
   }
 
   private onFrameNavigated(): void {
@@ -895,7 +895,7 @@ export class DebuggerModel extends SDKModel<EventTypes> {
     if (!callFrame) {
       throw new Error('No call frame selected');
     }
-    return callFrame.evaluate(options);
+    return await callFrame.evaluate(options);
   }
 
   functionDetailsPromise(remoteObject: RemoteObject): Promise<FunctionDetails|null> {
diff --git a/front_end/core/sdk/EmulationModel.ts b/front_end/core/sdk/EmulationModel.ts
index 8caba63ca2..92e9cbeedb 100644
--- a/front_end/core/sdk/EmulationModel.ts
+++ b/front_end/core/sdk/EmulationModel.ts
@@ -446,7 +446,7 @@ export class EmulationModel extends SDKModel<void> {
         value: this.#mediaConfiguration.get('prefers-reduced-transparency') ?? '',
       },
     ];
-    return this.emulateCSSMedia(type, features);
+    return await this.emulateCSSMedia(type, features);
   }
 }
 
diff --git a/front_end/core/sdk/FrameManager.ts b/front_end/core/sdk/FrameManager.ts
index 62c7ee8ba3..1d07d44e94 100644
--- a/front_end/core/sdk/FrameManager.ts
+++ b/front_end/core/sdk/FrameManager.ts
@@ -207,7 +207,7 @@ export class FrameManager extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
     if (frame && (!notInTarget || notInTarget !== frame.resourceTreeModel().target())) {
       return frame;
     }
-    return new Promise<ResourceTreeFrame>(resolve => {
+    return await new Promise<ResourceTreeFrame>(resolve => {
       const waiting = this.#awaitedFrames.get(frameId);
       if (waiting) {
         waiting.push({notInTarget, resolve});
diff --git a/front_end/core/sdk/HeapProfilerModel.ts b/front_end/core/sdk/HeapProfilerModel.ts
index cc68c13e2f..ce7b050227 100644
--- a/front_end/core/sdk/HeapProfilerModel.ts
+++ b/front_end/core/sdk/HeapProfilerModel.ts
@@ -59,7 +59,7 @@ export class HeapProfilerModel extends SDKModel<EventTypes> {
       throw new Error('Sampling profiler is not running.');
     }
     if (--this.#samplingProfilerDepth) {
-      return this.getSamplingProfile();
+      return await this.getSamplingProfile();
     }
     const response = await this.#heapProfilerAgent.invoke_stopSampling();
     if (response.getError()) {
diff --git a/front_end/core/sdk/NetworkManager.ts b/front_end/core/sdk/NetworkManager.ts
index 750a9e851b..95393462c4 100644
--- a/front_end/core/sdk/NetworkManager.ts
+++ b/front_end/core/sdk/NetworkManager.ts
@@ -368,8 +368,8 @@ export class NetworkManager extends SDKModel<EventTypes> {
     return result.status;
   }
 
-  async enableReportingApi(enable: boolean = true): Promise<Promise<Protocol.ProtocolResponseWithError>> {
-    return this.#networkAgent.invoke_enableReportingApi({enable});
+  async enableReportingApi(enable = true): Promise<Promise<Protocol.ProtocolResponseWithError>> {
+    return await this.#networkAgent.invoke_enableReportingApi({enable});
   }
 
   async loadNetworkResource(
@@ -1701,7 +1701,7 @@ export class MultitargetNetworkManager extends Common.ObjectWrapper.ObjectWrappe
     const allowRemoteFilePaths =
         Common.Settings.Settings.instance().moduleSetting('network.enable-remote-file-loading').get();
 
-    return new Promise(
+    return await new Promise(
         resolve => Host.ResourceLoader.load(url, headers, (success, _responseHeaders, content, errorDescription) => {
           resolve({success, content, errorDescription});
         }, allowRemoteFilePaths));
diff --git a/front_end/core/sdk/NetworkRequest.ts b/front_end/core/sdk/NetworkRequest.ts
index f1c23ea3a4..546541e7d6 100644
--- a/front_end/core/sdk/NetworkRequest.ts
+++ b/front_end/core/sdk/NetworkRequest.ts
@@ -1422,7 +1422,7 @@ export class NetworkRequest extends Common.ObjectWrapper.ObjectWrapper<EventType
   async searchInContent(query: string, caseSensitive: boolean, isRegex: boolean):
       Promise<TextUtils.ContentProvider.SearchMatch[]> {
     if (!this.#contentDataProvider) {
-      return NetworkManager.searchInRequest(this, query, caseSensitive, isRegex);
+      return await NetworkManager.searchInRequest(this, query, caseSensitive, isRegex);
     }
 
     const contentData = await this.requestContentData();
diff --git a/front_end/core/sdk/OverlayModel.ts b/front_end/core/sdk/OverlayModel.ts
index d95fcb71f9..52d37003b9 100644
--- a/front_end/core/sdk/OverlayModel.ts
+++ b/front_end/core/sdk/OverlayModel.ts
@@ -183,11 +183,11 @@ export class OverlayModel extends SDKModel<EventTypes> implements ProtocolProxyA
   }
 
   static async muteHighlight(): Promise<void[]> {
-    return Promise.all(TargetManager.instance().models(OverlayModel).map(model => model.suspendModel()));
+    return await Promise.all(TargetManager.instance().models(OverlayModel).map(model => model.suspendModel()));
   }
 
   static async unmuteHighlight(): Promise<void[]> {
-    return Promise.all(TargetManager.instance().models(OverlayModel).map(model => model.resumeModel()));
+    return await Promise.all(TargetManager.instance().models(OverlayModel).map(model => model.resumeModel()));
   }
 
   static highlightRect(rect: HighlightRect): void {
@@ -787,7 +787,7 @@ export class OverlayModel extends SDKModel<EventTypes> implements ProtocolProxyA
   }
 
   async hasStyleSheetText(url: Platform.DevToolsPath.UrlString): Promise<boolean> {
-    return this.#windowControls.initializeStyleSheetText(url);
+    return await this.#windowControls.initializeStyleSheetText(url);
   }
 }
 
diff --git a/front_end/core/sdk/OverlayPersistentHighlighter.ts b/front_end/core/sdk/OverlayPersistentHighlighter.ts
index 4777cdf9bb..ec82df0e1d 100644
--- a/front_end/core/sdk/OverlayPersistentHighlighter.ts
+++ b/front_end/core/sdk/OverlayPersistentHighlighter.ts
@@ -415,7 +415,7 @@ export class OverlayPersistentHighlighter {
     const currentURL = document ? document.documentURL : Platform.DevToolsPath.EmptyUrlString;
     await Promise.all(this.#persistentHighlightSetting.get().map(async persistentHighlight => {
       if (persistentHighlight.url === currentURL) {
-        return this.#model.getDOMModel().pushNodeByPathToFrontend(persistentHighlight.path).then(nodeId => {
+        return await this.#model.getDOMModel().pushNodeByPathToFrontend(persistentHighlight.path).then(nodeId => {
           const node = this.#model.getDOMModel().nodeForId(nodeId);
           if (!node) {
             return;
diff --git a/front_end/core/sdk/PageResourceLoader.ts b/front_end/core/sdk/PageResourceLoader.ts
index 4642a1f886..33c59fe44d 100644
--- a/front_end/core/sdk/PageResourceLoader.ts
+++ b/front_end/core/sdk/PageResourceLoader.ts
@@ -294,7 +294,7 @@ export class PageResourceLoader extends Common.ObjectWrapper.ObjectWrapper<Event
 
     let failureReason: string|null = null;
     if (this.#loadOverride) {
-      return this.#loadOverride(url);
+      return await this.#loadOverride(url);
     }
     const parsedURL = new Common.ParsedURL.ParsedURL(url);
     const eligibleForLoadFromTarget = getLoadThroughTargetSetting().get() && parsedURL && parsedURL.scheme !== 'file' &&
diff --git a/front_end/core/sdk/PreloadingModel.ts b/front_end/core/sdk/PreloadingModel.ts
index 9bda8ab294..ccd228167e 100644
--- a/front_end/core/sdk/PreloadingModel.ts
+++ b/front_end/core/sdk/PreloadingModel.ts
@@ -31,7 +31,7 @@ export interface WithId<I, V> {
 export class PreloadingModel extends SDKModel<EventTypes> {
   private agent: ProtocolProxyApi.PreloadApi;
   private loaderIds: Protocol.Network.LoaderId[] = [];
-  private targetJustAttached: boolean = true;
+  private targetJustAttached = true;
   private lastPrimaryPageModel: PreloadingModel|null = null;
   private documents: Map<Protocol.Network.LoaderId, DocumentPreloadingData> =
       new Map<Protocol.Network.LoaderId, DocumentPreloadingData>();
diff --git a/front_end/core/sdk/RehydratingConnection.ts b/front_end/core/sdk/RehydratingConnection.ts
index 18ccc8ba48..74ce141483 100644
--- a/front_end/core/sdk/RehydratingConnection.ts
+++ b/front_end/core/sdk/RehydratingConnection.ts
@@ -246,7 +246,7 @@ export class RehydratingSession extends RehydratingSessionBase {
     this.sessionAttachToTarget();
   }
 
-  override sendMessageToFrontend(payload: ServerMessage, attachSessionId: boolean = true): void {
+  override sendMessageToFrontend(payload: ServerMessage, attachSessionId = true): void {
     // Attach the session's Id to the message.
     if (this.sessionId !== 0 && attachSessionId) {
       payload.sessionId = this.sessionId;
diff --git a/front_end/core/sdk/RemoteObject.ts b/front_end/core/sdk/RemoteObject.ts
index fc2f329a5e..6d5b17c6ff 100644
--- a/front_end/core/sdk/RemoteObject.ts
+++ b/front_end/core/sdk/RemoteObject.ts
@@ -156,9 +156,8 @@ export abstract class RemoteObject {
     return {value: objectAsProtocolRemoteObject.value};
   }
 
-  static async loadFromObjectPerProto(
-      object: RemoteObject, generatePreview: boolean,
-      nonIndexedPropertiesOnly: boolean = false): Promise<GetPropertiesResult> {
+  static async loadFromObjectPerProto(object: RemoteObject, generatePreview: boolean, nonIndexedPropertiesOnly = false):
+      Promise<GetPropertiesResult> {
     const result = await Promise.all([
       object.getAllProperties(true /* accessorPropertiesOnly */, generatePreview, nonIndexedPropertiesOnly),
       object.getOwnProperties(generatePreview, nonIndexedPropertiesOnly),
@@ -391,14 +390,13 @@ export class RemoteObjectImpl extends RemoteObject {
     return this.#classNameInternal;
   }
 
-  override getOwnProperties(generatePreview: boolean, nonIndexedPropertiesOnly: boolean = false):
-      Promise<GetPropertiesResult> {
+  override getOwnProperties(generatePreview: boolean, nonIndexedPropertiesOnly = false): Promise<GetPropertiesResult> {
     return this.doGetProperties(true, false, nonIndexedPropertiesOnly, generatePreview);
   }
 
   override getAllProperties(
       accessorPropertiesOnly: boolean, generatePreview: boolean,
-      nonIndexedPropertiesOnly: boolean = false): Promise<GetPropertiesResult> {
+      nonIndexedPropertiesOnly = false): Promise<GetPropertiesResult> {
     return this.doGetProperties(false, accessorPropertiesOnly, nonIndexedPropertiesOnly, generatePreview);
   }
 
@@ -496,7 +494,7 @@ export class RemoteObjectImpl extends RemoteObject {
       void this.#runtimeAgent.invoke_releaseObject({objectId: response.result.objectId});
     }
 
-    return resultPromise;
+    return await resultPromise;
   }
 
   async doSetObjectPropertyValue(result: Protocol.Runtime.RemoteObject, name: Protocol.Runtime.CallArgument):
@@ -876,7 +874,7 @@ export class LocalJSONObject extends RemoteObject {
     return Boolean(Object.keys((this.valueInternal as Object)).length);
   }
 
-  override async getOwnProperties(_generatePreview: boolean, nonIndexedPropertiesOnly: boolean = false):
+  override async getOwnProperties(_generatePreview: boolean, nonIndexedPropertiesOnly = false):
       Promise<GetPropertiesResult> {
     function isArrayIndex(name: string): boolean {
       const index = Number(name) >>> 0;
@@ -892,7 +890,7 @@ export class LocalJSONObject extends RemoteObject {
 
   override async getAllProperties(
       accessorPropertiesOnly: boolean, generatePreview: boolean,
-      nonIndexedPropertiesOnly: boolean = false): Promise<GetPropertiesResult> {
+      nonIndexedPropertiesOnly = false): Promise<GetPropertiesResult> {
     if (accessorPropertiesOnly) {
       return {properties: [], internalProperties: null};
     }
diff --git a/front_end/core/sdk/Resource.ts b/front_end/core/sdk/Resource.ts
index a73f0e8e4f..e7b89da226 100644
--- a/front_end/core/sdk/Resource.ts
+++ b/front_end/core/sdk/Resource.ts
@@ -173,7 +173,7 @@ export class Resource implements TextUtils.ContentProvider.ContentProvider {
       return this.#contentData;
     }
     if (this.#pendingContentData) {
-      return this.#pendingContentData;
+      return await this.#pendingContentData;
     }
     this.#pendingContentData = this.innerRequestContent().then(contentData => {
       // If an error happended we don't set `this.#contentData` so future `requestContentData` will
@@ -184,7 +184,7 @@ export class Resource implements TextUtils.ContentProvider.ContentProvider {
       this.#pendingContentData = null;
       return contentData;
     });
-    return this.#pendingContentData;
+    return await this.#pendingContentData;
   }
 
   canonicalMimeType(): string {
@@ -197,7 +197,7 @@ export class Resource implements TextUtils.ContentProvider.ContentProvider {
       return [];
     }
     if (this.request) {
-      return this.request.searchInContent(query, caseSensitive, isRegex);
+      return await this.request.searchInContent(query, caseSensitive, isRegex);
     }
     const result = await this.#resourceTreeModel.target().pageAgent().invoke_searchInResource(
         {frameId: this.frameId, url: this.url, query, caseSensitive, isRegex});
@@ -215,7 +215,7 @@ export class Resource implements TextUtils.ContentProvider.ContentProvider {
   private async innerRequestContent(): Promise<TextUtils.ContentData.ContentDataOrError> {
     if (this.request) {
       // The `contentData` promise only resolves once the request is done.
-      return this.request.requestContentData();
+      return await this.request.requestContentData();
     }
 
     const response = await this.#resourceTreeModel.target().pageAgent().invoke_getResourceContent(
diff --git a/front_end/core/sdk/ResourceTreeModel.ts b/front_end/core/sdk/ResourceTreeModel.ts
index 6a24d0b7da..8ae17abef9 100644
--- a/front_end/core/sdk/ResourceTreeModel.ts
+++ b/front_end/core/sdk/ResourceTreeModel.ts
@@ -93,7 +93,7 @@ export class ResourceTreeModel extends SDKModel<EventTypes> {
   }
 
   async #buildResourceTree(): Promise<void> {
-    return this.agent.invoke_getResourceTree().then(event => {
+    return await this.agent.invoke_getResourceTree().then(event => {
       this.processCachedResources(event.getError() ? null : event.frameTree);
       if (this.mainFrame) {
         this.processPendingEvents(this.mainFrame);
@@ -475,7 +475,7 @@ export class ResourceTreeModel extends SDKModel<EventTypes> {
   }
 
   async getAppId(): Promise<Protocol.Page.GetAppIdResponse> {
-    return this.agent.invoke_getAppId();
+    return await this.agent.invoke_getAppId();
   }
 
   private executionContextComparator(a: ExecutionContext, b: ExecutionContext): number {
@@ -580,7 +580,7 @@ export class ResourceTreeModel extends SDKModel<EventTypes> {
   }
 
   async getMainStorageKey(): Promise<string|null> {
-    return this.mainFrame ? this.mainFrame.getStorageKey(/* forceFetch */ false) : null;
+    return this.mainFrame ? await this.mainFrame.getStorageKey(/* forceFetch */ false) : null;
   }
 
   getMainSecurityOrigin(): string|null {
@@ -998,16 +998,16 @@ export class ResourceTreeFrame {
     if (!parentFrame) {
       return null;
     }
-    return parentFrame.resourceTreeModel().domModel().getOwnerNodeForFrame(this.#idInternal);
+    return await parentFrame.resourceTreeModel().domModel().getOwnerNodeForFrame(this.#idInternal);
   }
 
   async getOwnerDOMNodeOrDocument(): Promise<DOMNode|null> {
     const deferredNode = await this.getOwnerDeferredDOMNode();
     if (deferredNode) {
-      return deferredNode.resolvePromise();
+      return await deferredNode.resolvePromise();
     }
     if (this.isOutermostFrame()) {
-      return this.resourceTreeModel().domModel().requestDocument();
+      return await this.resourceTreeModel().domModel().requestDocument();
     }
     return null;
   }
@@ -1023,14 +1023,14 @@ export class ResourceTreeFrame {
     };
 
     if (parentFrame) {
-      return highlightFrameOwner(parentFrame.resourceTreeModel().domModel());
+      return await highlightFrameOwner(parentFrame.resourceTreeModel().domModel());
     }
 
     // Fenced frames.
     if (parentTarget?.type() === Type.FRAME) {
       const domModel = parentTarget.model(DOMModel);
       if (domModel) {
-        return highlightFrameOwner(domModel);
+        return await highlightFrameOwner(domModel);
       }
     }
 
diff --git a/front_end/core/sdk/RuntimeModel.ts b/front_end/core/sdk/RuntimeModel.ts
index cb0da79957..e2dbf1e085 100644
--- a/front_end/core/sdk/RuntimeModel.ts
+++ b/front_end/core/sdk/RuntimeModel.ts
@@ -619,9 +619,9 @@ export class ExecutionContext {
   async evaluate(options: EvaluationOptions, userGesture: boolean, awaitPromise: boolean): Promise<EvaluationResult> {
     // FIXME: It will be moved to separate ExecutionContext.
     if (this.debuggerModel.selectedCallFrame()) {
-      return this.debuggerModel.evaluateOnSelectedCallFrame(options);
+      return await this.debuggerModel.evaluateOnSelectedCallFrame(options);
     }
-    return this.evaluateGlobal(options, userGesture, awaitPromise);
+    return await this.evaluateGlobal(options, userGesture, awaitPromise);
   }
 
   globalObject(objectGroup: string, generatePreview: boolean): Promise<EvaluationResult> {
diff --git a/front_end/core/sdk/Script.test.ts b/front_end/core/sdk/Script.test.ts
index a16f07e549..f7ab191e86 100644
--- a/front_end/core/sdk/Script.test.ts
+++ b/front_end/core/sdk/Script.test.ts
@@ -51,7 +51,7 @@ console.log("foo");
   });
 
   describe('editSource', () => {
-    function setupEditTest(scriptId: string, scriptSource: string = '') {
+    function setupEditTest(scriptId: string, scriptSource = '') {
       const target = createTarget();
       const model = target.model(SDK.DebuggerModel.DebuggerModel) as SDK.DebuggerModel.DebuggerModel;
       dispatchEvent(target, 'Debugger.scriptParsed', {
diff --git a/front_end/core/sdk/Script.ts b/front_end/core/sdk/Script.ts
index 7633d0908d..fbd00d2b92 100644
--- a/front_end/core/sdk/Script.ts
+++ b/front_end/core/sdk/Script.ts
@@ -311,7 +311,7 @@ export class Script implements TextUtils.ContentProvider.ContentProvider, FrameA
   async getWasmBytecode(): Promise<ArrayBuffer> {
     const base64 = await this.debuggerModel.target().debuggerAgent().invoke_getWasmBytecode({scriptId: this.scriptId});
     const response = await fetch(`data:application/wasm;base64,${base64.bytecode}`);
-    return response.arrayBuffer();
+    return await response.arrayBuffer();
   }
 
   originalContentProvider(): TextUtils.ContentProvider.ContentProvider {
diff --git a/front_end/core/sdk/ServerSentEvents.ts b/front_end/core/sdk/ServerSentEvents.ts
index a6be63aaf1..1183ca55f3 100644
--- a/front_end/core/sdk/ServerSentEvents.ts
+++ b/front_end/core/sdk/ServerSentEvents.ts
@@ -23,7 +23,7 @@ export class ServerSentEvents {
 
   // In the case where we parse the events ourselves we use the time of the last 'dataReceived'
   // event for all the events that come out of the corresponding chunk of data.
-  #lastDataReceivedTime: number = 0;
+  #lastDataReceivedTime = 0;
 
   readonly #eventSourceMessages: EventSourceMessage[] = [];
 
diff --git a/front_end/core/sdk/StorageBucketsModel.ts b/front_end/core/sdk/StorageBucketsModel.ts
index 1ada4ca6f0..d9743208c3 100644
--- a/front_end/core/sdk/StorageBucketsModel.ts
+++ b/front_end/core/sdk/StorageBucketsModel.ts
@@ -37,7 +37,7 @@ import {Events as StorageKeyManagerEvents, StorageKeyManager} from './StorageKey
 import {Capability, type Target} from './Target.js';
 
 export class StorageBucketsModel extends SDKModel<EventTypes> implements ProtocolProxyApi.StorageDispatcher {
-  private enabled: boolean = false;
+  private enabled = false;
   readonly storageAgent: ProtocolProxyApi.StorageApi;
   private readonly storageKeyManager: StorageKeyManager|null;
   private bucketsById = new Map<string, Protocol.Storage.StorageBucketInfo>();
diff --git a/front_end/core/sdk/StorageKeyManager.test.ts b/front_end/core/sdk/StorageKeyManager.test.ts
index fe3a104263..97c844fadf 100644
--- a/front_end/core/sdk/StorageKeyManager.test.ts
+++ b/front_end/core/sdk/StorageKeyManager.test.ts
@@ -18,7 +18,7 @@ describeWithMockConnection('StorageKeyManager', () => {
   });
 
   it('updates storage keys and emits events correctly', () => {
-    let eventFired: boolean = false;
+    let eventFired = false;
     const keys = ['storagekey1', 'storagekey2'];
 
     assert.isEmpty(manager.storageKeys());
diff --git a/front_end/core/sdk/Target.ts b/front_end/core/sdk/Target.ts
index 34687cd9a0..a9fdacaa5b 100644
--- a/front_end/core/sdk/Target.ts
+++ b/front_end/core/sdk/Target.ts
@@ -32,7 +32,7 @@ export class Target extends ProtocolClient.InspectorBackend.TargetBase {
    * the page crashes, but a reload fixes it and the targets get restored (see
    * crbug.com/387258086).
    */
-  #hasCrashed: boolean = false;
+  #hasCrashed = false;
   #targetInfoInternal: Protocol.Target.TargetInfo|undefined;
   #creatingModels?: boolean;
 
diff --git a/front_end/entrypoints/device_mode_emulation_frame/device_mode_emulation_frame.ts b/front_end/entrypoints/device_mode_emulation_frame/device_mode_emulation_frame.ts
index d3a20d2b51..7acb9f3054 100644
--- a/front_end/entrypoints/device_mode_emulation_frame/device_mode_emulation_frame.ts
+++ b/front_end/entrypoints/device_mode_emulation_frame/device_mode_emulation_frame.ts
@@ -6,7 +6,6 @@ import '../../core/dom_extension/dom_extension.js';
 import '../../Images/Images.js';
 
 if (window.opener) {
-  // @ts-ignore TypeScript doesn't know about `Emulation` on `Window`.
   const app = window.opener.Emulation.AdvancedApp.instance();
   app.deviceModeEmulationFrameLoaded(document);
 }
diff --git a/front_end/entrypoints/devtools_app/devtools_app.ts b/front_end/entrypoints/devtools_app/devtools_app.ts
index f5f996a089..2644b17c03 100644
--- a/front_end/entrypoints/devtools_app/devtools_app.ts
+++ b/front_end/entrypoints/devtools_app/devtools_app.ts
@@ -31,6 +31,6 @@ import '../../panels/whats_new/whats_new-meta.js';
 import * as Root from '../../core/root/root.js';
 import * as Main from '../main/main.js';
 
-// @ts-ignore Exposed for legacy layout tests
+// @ts-expect-error Exposed for legacy layout tests
 self.runtime = Root.Runtime.Runtime.instance({forceNew: true});
 new Main.MainImpl.MainImpl();
diff --git a/front_end/entrypoints/formatter_worker/ESTreeWalker.ts b/front_end/entrypoints/formatter_worker/ESTreeWalker.ts
index 3707d0f78c..9a4a6c705c 100644
--- a/front_end/entrypoints/formatter_worker/ESTreeWalker.ts
+++ b/front_end/entrypoints/formatter_worker/ESTreeWalker.ts
@@ -41,7 +41,7 @@ export class ESTreeWalker {
       this.#innerWalk(templateLiteral.quasis[expressionsLength], templateLiteral);
     } else {
       for (let i = 0; i < walkOrder.length; ++i) {
-        // @ts-ignore We are doing type traversal here, but the strings
+        // @ts-expect-error We are doing type traversal here, but the strings
         // in _walkOrder are not mapping. Preferably, we would use the
         // properties as defined in the types, but we can't do that yet.
         // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration
diff --git a/front_end/entrypoints/formatter_worker/JavaScriptFormatter.ts b/front_end/entrypoints/formatter_worker/JavaScriptFormatter.ts
index 5df8b31fba..b3ba39bc9c 100644
--- a/front_end/entrypoints/formatter_worker/JavaScriptFormatter.ts
+++ b/front_end/entrypoints/formatter_worker/JavaScriptFormatter.ts
@@ -63,7 +63,7 @@ export class JavaScriptFormatter {
     });
     this.#tokenizer = new AcornTokenizer(this.#content, tokens);
     const walker = new ESTreeWalker(this.#beforeVisit.bind(this), this.#afterVisit.bind(this));
-    // @ts-ignore Technically, the acorn Node type is a subclass of Acorn.ESTree.Node.
+    // @ts-expect-error Technically, the acorn Node type is a subclass of Acorn.ESTree.Node.
     // However, the acorn package currently exports its type without specifying
     // this relationship. So while this is allowed on runtime, we can't properly
     // typecheck it.
@@ -104,7 +104,7 @@ export class JavaScriptFormatter {
     let token;
     while ((token = this.#tokenizer.peekToken()) && token.start < node.start) {
       const token = (this.#tokenizer.nextToken() as TokenOrComment);
-      // @ts-ignore Same reason as above about Acorn types and ESTree types
+      // @ts-expect-error Same reason as above about Acorn types and ESTree types
       const format = this.#formatToken(node.parent, token);
       this.#push(token, format);
     }
@@ -256,7 +256,7 @@ export class JavaScriptFormatter {
         let allVariablesInitialized = true;
         const declarations = (node.declarations as Acorn.ESTree.Node[]);
         for (let i = 0; i < declarations.length; ++i) {
-          // @ts-ignore We are doing a subtype check, without properly checking whether
+          // @ts-expect-error We are doing a subtype check, without properly checking whether
           // it exists. We can't fix that, unless we use proper typechecking
           allVariablesInitialized = allVariablesInitialized && Boolean(declarations[i].init);
         }
@@ -419,7 +419,7 @@ export class JavaScriptFormatter {
       }
       if (node.parent && node.parent.type === 'CatchClause') {
         const parentNode = (node.parent as Acorn.ESTree.CatchClause);
-        // @ts-ignore We are doing a subtype check, without properly checking whether
+        // @ts-expect-error We are doing a subtype check, without properly checking whether
         // it exists. We can't fix that, unless we use proper typechecking
         if (parentNode.parent && parentNode.parent.finalizer) {
           return 's';
diff --git a/front_end/entrypoints/formatter_worker/ScopeParser.ts b/front_end/entrypoints/formatter_worker/ScopeParser.ts
index 7fec79fefb..367f22d563 100644
--- a/front_end/entrypoints/formatter_worker/ScopeParser.ts
+++ b/front_end/entrypoints/formatter_worker/ScopeParser.ts
@@ -436,7 +436,7 @@ export class ScopeVariableAnalysis {
 
   #addVariable(
       name: string, offset: number, definitionKind: DefinitionKind = DefinitionKind.NONE,
-      isShorthandAssignmentProperty: boolean = false): void {
+      isShorthandAssignmentProperty = false): void {
     this.#allNames.add(name);
     this.#currentScope.addVariable(name, offset, definitionKind, isShorthandAssignmentProperty);
   }
diff --git a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshot.ts b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshot.ts
index 9dda6c5d69..79a837af5f 100644
--- a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshot.ts
+++ b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshot.ts
@@ -1057,15 +1057,15 @@ export abstract class HeapSnapshot {
       if (!filter) {
         throw new Error('Unable to create filter');
       }
-      // @ts-ignore key can be added as a static property
+      // @ts-expect-error key can be added as a static property
       filter.key = 'AllocationNodeId: ' + allocationNodeId;
     } else if (typeof minNodeId === 'number' && typeof maxNodeId === 'number') {
       filter = this.createNodeIdFilter(minNodeId, maxNodeId);
-      // @ts-ignore key can be added as a static property
+      // @ts-expect-error key can be added as a static property
       filter.key = 'NodeIdRange: ' + minNodeId + '..' + maxNodeId;
     } else if (filterName !== undefined) {
       filter = this.createNamedFilter(filterName);
-      // @ts-ignore key can be added as a static property
+      // @ts-expect-error key can be added as a static property
       filter.key = 'NamedFilter: ' + filterName;
     }
     return filter;
@@ -1138,7 +1138,7 @@ export abstract class HeapSnapshot {
   aggregatesWithFilter(nodeFilter: HeapSnapshotModel.HeapSnapshotModel.NodeFilter):
       {[x: string]: HeapSnapshotModel.HeapSnapshotModel.Aggregate} {
     const filter = this.createFilter(nodeFilter);
-    // @ts-ignore key is added in createFilter
+    // @ts-expect-error key is added in createFilter
     const key = filter ? filter.key : 'allObjects';
     return this.getAggregatesByClassKey(false, key, filter);
   }
@@ -2860,7 +2860,7 @@ export class HeapSnapshotEdgesProvider extends HeapSnapshotItemProvider {
     function compareEdgeField(fieldName: string, ascending: boolean, indexA: number, indexB: number): number {
       edgeA.edgeIndex = indexA;
       edgeB.edgeIndex = indexB;
-      let result: number = 0;
+      let result = 0;
       if (fieldName === '!edgeName') {
         if (edgeB.name() === '__proto__') {
           return -1;
@@ -3685,7 +3685,7 @@ export class JSHeapSnapshotEdge extends HeapSnapshotEdge {
     if (!this.isShortcut()) {
       return this.hasStringNameInternal();
     }
-    // @ts-ignore parseInt is successful against numbers.
+    // @ts-expect-error parseInt is successful against numbers.
     return isNaN(parseInt(this.nameInternal(), 10));
   }
 
@@ -3718,7 +3718,7 @@ export class JSHeapSnapshotEdge extends HeapSnapshotEdge {
     if (!this.isShortcut()) {
       return String(name);
     }
-    // @ts-ignore parseInt is successful against numbers.
+    // @ts-expect-error parseInt is successful against numbers.
     const numName = parseInt(name, 10);
     return String(isNaN(numName) ? name : numName);
   }
diff --git a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
index 2daf9602cf..5bb9615077 100644
--- a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
+++ b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotLoader.ts
@@ -44,7 +44,7 @@ export class HeapSnapshotLoader {
   #snapshot?: {[x: string]: any};
   #array!: Platform.TypedArrayUtilities.BigUint32Array|null;
   #arrayIndex!: number;
-  #json: string = '';
+  #json = '';
   constructor(dispatcher: HeapSnapshotWorkerDispatcher) {
     this.#reset();
     this.#progress = new HeapSnapshotProgress(dispatcher);
diff --git a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotWorkerDispatcher.ts b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotWorkerDispatcher.ts
index bfe06601df..849c619d53 100644
--- a/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotWorkerDispatcher.ts
+++ b/front_end/entrypoints/heap_snapshot_worker/HeapSnapshotWorkerDispatcher.ts
@@ -94,13 +94,13 @@ export class HeapSnapshotWorkerDispatcher {
         case 'evaluateForTest': {
           try {
             // Make 'HeapSnapshotWorker' and 'HeapSnapshotModel' available to web tests. 'eval' can't use 'import'.
-            // @ts-ignore
+            // @ts-expect-error
             globalThis.HeapSnapshotWorker = {
               AllocationProfile,
               HeapSnapshot,
               HeapSnapshotLoader,
             };
-            // @ts-ignore
+            // @ts-expect-error
             globalThis.HeapSnapshotModel = HeapSnapshotModel;
             response.result = self.eval(data.source);
           } catch (error) {
diff --git a/front_end/entrypoints/lighthouse_worker/LighthouseWorkerService.ts b/front_end/entrypoints/lighthouse_worker/LighthouseWorkerService.ts
index 57363e8bff..f3956170a0 100644
--- a/front_end/entrypoints/lighthouse_worker/LighthouseWorkerService.ts
+++ b/front_end/entrypoints/lighthouse_worker/LighthouseWorkerService.ts
@@ -224,7 +224,6 @@ async function onFrontendMessage(event: MessageEvent): Promise<void> {
 self.onmessage = onFrontendMessage;
 
 // Make lighthouse and traceviewer happy.
-// @ts-ignore https://github.com/GoogleChrome/lighthouse/issues/11628
 globalThis.global = self;
 // @ts-expect-error https://github.com/GoogleChrome/lighthouse/issues/11628
 globalThis.global.isVinn = true;
diff --git a/front_end/entrypoints/main/ExecutionContextSelector.test.ts b/front_end/entrypoints/main/ExecutionContextSelector.test.ts
index 1e4a91e54b..81ebce8d8f 100644
--- a/front_end/entrypoints/main/ExecutionContextSelector.test.ts
+++ b/front_end/entrypoints/main/ExecutionContextSelector.test.ts
@@ -30,7 +30,7 @@ describeWithMockConnection('ExecutionContextSelector', () => {
 
     const contextSetFlavor = sinon.spy(UI.Context.Context.instance(), 'setFlavor');
 
-    const sentExecutionContextCreated = (target: SDK.Target.Target, includeFrameId: boolean = true) => {
+    const sentExecutionContextCreated = (target: SDK.Target.Target, includeFrameId = true) => {
       const frameId = includeFrameId ? getMainFrame(target).id : undefined;
 
       const runtimeModel = target.model(SDK.RuntimeModel.RuntimeModel);
diff --git a/front_end/entrypoints/main/MainImpl.ts b/front_end/entrypoints/main/MainImpl.ts
index 297ddcf85f..1122bc10cd 100644
--- a/front_end/entrypoints/main/MainImpl.ts
+++ b/front_end/entrypoints/main/MainImpl.ts
@@ -184,17 +184,17 @@ export class MainImpl {
   }
 
   #initializeGlobalsForLayoutTests(): void {
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.Extensions ||= {};
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.Host ||= {};
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.Host.userMetrics ||= Host.userMetrics;
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.Host.UserMetrics ||= Host.UserMetrics;
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.ProtocolClient ||= {};
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.ProtocolClient.test ||= ProtocolClient.InspectorBackend.test;
   }
 
@@ -504,7 +504,7 @@ export class MainImpl {
       targetManager,
       debuggerWorkspaceBinding: Bindings.DebuggerWorkspaceBinding.DebuggerWorkspaceBinding.instance(),
     });
-    // @ts-ignore e2e test global
+    // @ts-expect-error e2e test global
     self.Extensions.extensionServer = Extensions.ExtensionServer.ExtensionServer.instance({forceNew: true});
 
     new Persistence.FileSystemWorkspaceBinding.FileSystemWorkspaceBinding(
@@ -676,7 +676,7 @@ export class MainImpl {
     const promises: Array<Promise<void>> =
         Common.Runnable.lateInitializationRunnables().map(async lateInitializationLoader => {
           const runnable = await lateInitializationLoader();
-          return runnable.run();
+          return await runnable.run();
         });
     if (Root.Runtime.experiments.isEnabled('live-heap-profile')) {
       const PerfUI = await import('../../ui/legacy/components/perf_ui/perf_ui.js');
@@ -749,7 +749,7 @@ export class MainImpl {
 
   #redispatchClipboardEvent(event: Event): void {
     const eventCopy = new CustomEvent('clipboard-' + event.type, {bubbles: true});
-    // @ts-ignore Used in ElementsTreeOutline
+    // @ts-expect-error Used in ElementsTreeOutline
     eventCopy['original'] = event;
     const document = event.target && (event.target as HTMLElement).ownerDocument;
     const target = document ? Platform.DOMUtilities.deepActiveElement(document) : null;
@@ -784,9 +784,9 @@ export class MainImpl {
   static instanceForTest: MainImpl|null = null;
 }
 
-// @ts-ignore Exported for Tests.js
+// @ts-expect-error Exported for Tests.js
 globalThis.Main = globalThis.Main || {};
-// @ts-ignore Exported for Tests.js
+// @ts-expect-error Exported for Tests.js
 globalThis.Main.Main = MainImpl;
 
 export class ZoomActionDelegate implements UI.ActionRegistration.ActionDelegate {
diff --git a/front_end/entrypoints/node_app/node_app.ts b/front_end/entrypoints/node_app/node_app.ts
index cec9239505..3873216a76 100644
--- a/front_end/entrypoints/node_app/node_app.ts
+++ b/front_end/entrypoints/node_app/node_app.ts
@@ -76,7 +76,7 @@ UI.ViewManager.registerViewExtension({
   },
 });
 
-// @ts-ignore Exposed for legacy layout tests
+// @ts-expect-error Exposed for legacy layout tests
 self.runtime = Root.Runtime.Runtime.instance({forceNew: true});
 Common.Runnable.registerEarlyInitializationRunnable(NodeMainImpl.instance);
 new Main.MainImpl.MainImpl();
diff --git a/front_end/entrypoints/worker_app/worker_app.ts b/front_end/entrypoints/worker_app/worker_app.ts
index 4004b5dc05..ab9c9f0cbb 100644
--- a/front_end/entrypoints/worker_app/worker_app.ts
+++ b/front_end/entrypoints/worker_app/worker_app.ts
@@ -15,6 +15,6 @@ import './WorkerMain.js';
 import * as Root from '../../core/root/root.js';
 import * as Main from '../main/main.js';
 
-// @ts-ignore Exposed for legacy layout tests
+// @ts-expect-error Exposed for legacy layout tests
 self.runtime = Root.Runtime.Runtime.instance({forceNew: true});
 new Main.MainImpl.MainImpl();
diff --git a/front_end/generated/InspectorBackendCommands.js b/front_end/generated/InspectorBackendCommands.js
index dd9ae5ca02..3ab5ac84aa 100644
--- a/front_end/generated/InspectorBackendCommands.js
+++ b/front_end/generated/InspectorBackendCommands.js
@@ -31,7 +31,7 @@
  *  ): void,
  * }}
  */
-// @ts-ignore typedef
+// @ts-expect-error typedef
 export let InspectorBackendAPI;
 
 /**
diff --git a/front_end/legacy_test_runner/legacy_test_runner.ts b/front_end/legacy_test_runner/legacy_test_runner.ts
index b805546c3c..ebeec75533 100644
--- a/front_end/legacy_test_runner/legacy_test_runner.ts
+++ b/front_end/legacy_test_runner/legacy_test_runner.ts
@@ -5,10 +5,10 @@
 import '../entrypoints/devtools_app/devtools_app.js';
 import './test_runner/test_runner.js';
 
-// @ts-ignore
+// @ts-expect-error
 if (self.testRunner) {
-  // @ts-ignore
+  // @ts-expect-error
   testRunner.dumpAsText();
-  // @ts-ignore
+  // @ts-expect-error
   testRunner.waitUntilDone();
 }
diff --git a/front_end/models/autofill_manager/AutofillManager.ts b/front_end/models/autofill_manager/AutofillManager.ts
index 8bd4554590..e4fb29431f 100644
--- a/front_end/models/autofill_manager/AutofillManager.ts
+++ b/front_end/models/autofill_manager/AutofillManager.ts
@@ -14,7 +14,7 @@ let autofillManagerInstance: AutofillManager;
 
 export class AutofillManager extends Common.ObjectWrapper.ObjectWrapper<EventTypes> {
   #autoOpenViewSetting: Common.Settings.Setting<boolean>;
-  #address: string = '';
+  #address = '';
   #filledFields: Protocol.Autofill.FilledField[] = [];
   #matches: Match[] = [];
   #autofillModel: SDK.AutofillModel.AutofillModel|null = null;
diff --git a/front_end/models/bindings/DebuggerLanguagePlugins.ts b/front_end/models/bindings/DebuggerLanguagePlugins.ts
index 72f1cc85c5..412bfabf78 100644
--- a/front_end/models/bindings/DebuggerLanguagePlugins.ts
+++ b/front_end/models/bindings/DebuggerLanguagePlugins.ts
@@ -990,7 +990,7 @@ export class DebuggerLanguagePluginManager implements
 
     try {
       // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-      // @ts-ignore
+      // @ts-expect-error
       const locations = await plugin.getInlinedFunctionRanges(pluginLocation);
       return locations.map(
           m => ({
@@ -1027,7 +1027,7 @@ export class DebuggerLanguagePluginManager implements
 
     try {
       // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-      // @ts-ignore
+      // @ts-expect-error
       const locations = await plugin.getInlinedCalleesRanges(pluginLocation);
       return locations.map(
           m => ({
diff --git a/front_end/models/bindings/DebuggerWorkspaceBinding.ts b/front_end/models/bindings/DebuggerWorkspaceBinding.ts
index aa4c1ff539..b18c299213 100644
--- a/front_end/models/bindings/DebuggerWorkspaceBinding.ts
+++ b/front_end/models/bindings/DebuggerWorkspaceBinding.ts
@@ -186,7 +186,7 @@ export class DebuggerWorkspaceBinding implements SDK.TargetManager.SDKModelObser
     }
     const liveLocationPromise = modelData.createLiveLocation(rawLocation, updateDelegate, locationPool);
     this.recordLiveLocationChange(liveLocationPromise);
-    return liveLocationPromise;
+    return await liveLocationPromise;
   }
 
   async createStackTraceTopFrameLiveLocation(
@@ -196,7 +196,7 @@ export class DebuggerWorkspaceBinding implements SDK.TargetManager.SDKModelObser
     const locationPromise =
         StackTraceTopFrameLocation.createStackTraceTopFrameLocation(rawLocations, this, updateDelegate, locationPool);
     this.recordLiveLocationChange(locationPromise);
-    return locationPromise;
+    return await locationPromise;
   }
 
   async createCallFrameLiveLocation(
@@ -247,14 +247,14 @@ export class DebuggerWorkspaceBinding implements SDK.TargetManager.SDKModelObser
       debuggerModel: SDK.DebuggerModel.DebuggerModel, url: Platform.DevToolsPath.UrlString,
       isContentScript: boolean): Promise<Workspace.UISourceCode.UISourceCode> {
     const uiSourceCode = this.uiSourceCodeForSourceMapSourceURL(debuggerModel, url, isContentScript);
-    return uiSourceCode || this.waitForUISourceCodeAdded(url, debuggerModel.target());
+    return await (uiSourceCode || this.waitForUISourceCodeAdded(url, debuggerModel.target()));
   }
 
   async uiSourceCodeForDebuggerLanguagePluginSourceURLPromise(
       debuggerModel: SDK.DebuggerModel.DebuggerModel,
       url: Platform.DevToolsPath.UrlString): Promise<Workspace.UISourceCode.UISourceCode|null> {
     const uiSourceCode = this.pluginManager.uiSourceCodeForURL(debuggerModel, url);
-    return uiSourceCode || this.waitForUISourceCodeAdded(url, debuggerModel.target());
+    return await (uiSourceCode || this.waitForUISourceCodeAdded(url, debuggerModel.target()));
   }
 
   uiSourceCodeForScript(script: SDK.Script.Script): Workspace.UISourceCode.UISourceCode|null {
@@ -593,7 +593,7 @@ export class Location extends LiveLocationWithPool {
 
   override async uiLocation(): Promise<Workspace.UISourceCode.UILocation|null> {
     const debuggerModelLocation = this.rawLocation;
-    return this.#binding.rawLocationToUILocation(debuggerModelLocation);
+    return await this.#binding.rawLocationToUILocation(debuggerModelLocation);
   }
 
   override dispose(): void {
@@ -634,11 +634,11 @@ class StackTraceTopFrameLocation extends LiveLocationWithPool {
   }
 
   override async uiLocation(): Promise<Workspace.UISourceCode.UILocation|null> {
-    return this.#current ? this.#current.uiLocation() : null;
+    return this.#current ? await this.#current.uiLocation() : null;
   }
 
   override async isIgnoreListed(): Promise<boolean> {
-    return this.#current ? this.#current.isIgnoreListed() : false;
+    return this.#current ? await this.#current.isIgnoreListed() : false;
   }
 
   override dispose(): void {
diff --git a/front_end/models/bindings/FileUtils.ts b/front_end/models/bindings/FileUtils.ts
index 7903ec2607..a6a55b5ff6 100644
--- a/front_end/models/bindings/FileUtils.ts
+++ b/front_end/models/bindings/FileUtils.ts
@@ -98,7 +98,7 @@ export class ChunkedFileReader implements ChunkedReader {
     this.#output = output;
     void this.loadChunk();
 
-    return new Promise(resolve => {
+    return await new Promise(resolve => {
       this.#transferFinished = resolve;
     });
   }
@@ -192,7 +192,7 @@ export class ChunkedFileReader implements ChunkedReader {
       if (done || !value) {
         // Write empty string to inform of file end
         await this.#output.write('', true);
-        return this.finishRead();
+        return await this.finishRead();
       }
       void this.decodeChunkBuffer(value.buffer, false);
     }
diff --git a/front_end/models/bindings/TempFile.ts b/front_end/models/bindings/TempFile.ts
index f2ab0bc473..01993d50cb 100644
--- a/front_end/models/bindings/TempFile.ts
+++ b/front_end/models/bindings/TempFile.ts
@@ -84,7 +84,7 @@ export class TempFile {
       return null;
     }
     const reader = new ChunkedFileReader((this.#lastBlob as File), 10 * 1000 * 1000, progress);
-    return reader.read(outputStream).then(success => success ? null : reader.error());
+    return await reader.read(outputStream).then(success => success ? null : reader.error());
   }
 
   remove(): void {
diff --git a/front_end/models/breakpoints/BreakpointManager.ts b/front_end/models/breakpoints/BreakpointManager.ts
index ba57cd6130..a9034e4222 100644
--- a/front_end/models/breakpoints/BreakpointManager.ts
+++ b/front_end/models/breakpoints/BreakpointManager.ts
@@ -612,7 +612,7 @@ export class Breakpoint implements SDK.TargetManager.SDKModelObserver<SDK.Debugg
       const modelBreakpoints = Array.from(this.#modelBreakpoints.values());
       await Promise.all(modelBreakpoints.map(async modelBreakpoint => {
         await modelBreakpoint.resetBreakpoint();
-        return this.#updateModel(modelBreakpoint);
+        return await this.#updateModel(modelBreakpoint);
       }));
     }
   }
@@ -847,7 +847,7 @@ export class Breakpoint implements SDK.TargetManager.SDKModelObserver<SDK.Debugg
         this.addAllUnboundLocations();
       }
     }
-    return this.#updateModels();
+    return await this.#updateModels();
   }
 
   async remove(keepInStorage: boolean): Promise<void> {
diff --git a/front_end/models/cpu_profile/CPUProfileDataModel.ts b/front_end/models/cpu_profile/CPUProfileDataModel.ts
index 169ceb9ba1..d67cd4091b 100644
--- a/front_end/models/cpu_profile/CPUProfileDataModel.ts
+++ b/front_end/models/cpu_profile/CPUProfileDataModel.ts
@@ -72,13 +72,13 @@ export class CPUProfileDataModel extends ProfileTreeModel {
   #stackChildrenDuration?: number[];
   constructor(profile: ExtendedProfile) {
     super();
-    // @ts-ignore Legacy types
+    // @ts-expect-error Legacy types
     const isLegacyFormat = Boolean(profile['head']);
     if (isLegacyFormat) {
       // Legacy format contains raw timestamps and start/stop times are in seconds.
       this.profileStartTime = profile.startTime * 1000;
       this.profileEndTime = profile.endTime * 1000;
-      // @ts-ignore Legacy types
+      // @ts-expect-error Legacy types
       this.timestamps = profile.timestamps;
       this.compatibilityConversionHeadToNodes(profile);
     } else {
@@ -110,19 +110,19 @@ export class CPUProfileDataModel extends ProfileTreeModel {
   }
 
   private compatibilityConversionHeadToNodes(profile: Protocol.Profiler.Profile): void {
-    // @ts-ignore Legacy types
+    // @ts-expect-error Legacy types
     if (!profile.head || profile.nodes) {
       return;
     }
     const nodes: Protocol.Profiler.ProfileNode[] = [];
-    // @ts-ignore Legacy types
+    // @ts-expect-error Legacy types
     convertNodesTree(profile.head);
     profile.nodes = nodes;
-    // @ts-ignore Legacy types
+    // @ts-expect-error Legacy types
     delete profile.head;
     function convertNodesTree(node: Protocol.Profiler.ProfileNode): number {
       nodes.push(node);
-      // @ts-ignore Legacy types
+      // @ts-expect-error Legacy types
       node.children = (node.children as Protocol.Profiler.ProfileNode[]).map(convertNodesTree);
       return node.id;
     }
@@ -163,7 +163,7 @@ export class CPUProfileDataModel extends ProfileTreeModel {
       nodes[0].children = [];
       for (let i = 1; i < nodes.length; ++i) {
         const node = nodes[i];
-        // @ts-ignore Legacy types
+        // @ts-expect-error Legacy types
         const parentNode = protocolNodeById.get(node.parent);
         if (!parentNode) {
           continue;
diff --git a/front_end/models/crux-manager/CrUXManager.ts b/front_end/models/crux-manager/CrUXManager.ts
index 0ecf596b63..cc16d6d02a 100644
--- a/front_end/models/crux-manager/CrUXManager.ts
+++ b/front_end/models/crux-manager/CrUXManager.ts
@@ -233,7 +233,7 @@ export class CrUXManager extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
   }
 
   async getFieldDataForCurrentPageForTesting(): Promise<PageResult> {
-    return this.#getFieldDataForCurrentPage();
+    return await this.#getFieldDataForCurrentPage();
   }
 
   /**
diff --git a/front_end/models/emulation/DeviceModeModel.ts b/front_end/models/emulation/DeviceModeModel.ts
index bde74580b2..bf24e1ef9d 100644
--- a/front_end/models/emulation/DeviceModeModel.ts
+++ b/front_end/models/emulation/DeviceModeModel.ts
@@ -782,7 +782,7 @@ export class DeviceModeModel extends Common.ObjectWrapper.ObjectWrapper<EventTyp
         deviceMetrics.height = orientation.height;
         const dispFeature = this.getDisplayFeature();
         if (dispFeature) {
-          // @ts-ignore: displayFeature isn't in protocol.ts but is an
+          // @ts-expect-error: displayFeature isn't in protocol.ts but is an
           // experimental flag:
           // https://chromedevtools.github.io/devtools-protocol/tot/Emulation/#method-setDeviceMetricsOverride
           deviceMetrics.displayFeature = dispFeature;
diff --git a/front_end/models/extensions/ExtensionAPI.ts b/front_end/models/extensions/ExtensionAPI.ts
index 05bf82c2ca..ca15aebf45 100644
--- a/front_end/models/extensions/ExtensionAPI.ts
+++ b/front_end/models/extensions/ExtensionAPI.ts
@@ -829,10 +829,10 @@ self.injectedExtensionAPI = function(
     async function dispatchMethodCall(request: PrivateAPI.RecorderExtensionRequests): Promise<unknown> {
       switch (request.method) {
         case PrivateAPI.RecorderExtensionPluginCommands.Stringify:
-          return (plugin as PublicAPI.Chrome.DevTools.RecorderExtensionExportPlugin)
+          return await (plugin as PublicAPI.Chrome.DevTools.RecorderExtensionExportPlugin)
               .stringify(request.parameters.recording);
         case PrivateAPI.RecorderExtensionPluginCommands.StringifyStep:
-          return (plugin as PublicAPI.Chrome.DevTools.RecorderExtensionExportPlugin)
+          return await (plugin as PublicAPI.Chrome.DevTools.RecorderExtensionExportPlugin)
               .stringifyStep(request.parameters.step);
         case PrivateAPI.RecorderExtensionPluginCommands.Replay:
           try {
@@ -1006,18 +1006,18 @@ self.injectedExtensionAPI = function(
     },
     getWasmLocal: async function(
         this: APIImpl.LanguageExtensions, local: number, stopId: number): Promise<PublicAPI.Chrome.DevTools.WasmValue> {
-      return new Promise(
+      return await new Promise(
           resolve => extensionServer.sendRequest({command: PrivateAPI.Commands.GetWasmLocal, local, stopId}, resolve));
     },
     getWasmGlobal: async function(this: APIImpl.LanguageExtensions, global: number, stopId: number):
         Promise<PublicAPI.Chrome.DevTools.WasmValue> {
-          return new Promise(
+          return await new Promise(
               resolve =>
                   extensionServer.sendRequest({command: PrivateAPI.Commands.GetWasmGlobal, global, stopId}, resolve));
         },
     getWasmOp: async function(this: APIImpl.LanguageExtensions, op: number, stopId: number):
         Promise<PublicAPI.Chrome.DevTools.WasmValue> {
-          return new Promise(
+          return await new Promise(
               resolve => extensionServer.sendRequest({command: PrivateAPI.Commands.GetWasmOp, op, stopId}, resolve));
         },
 
diff --git a/front_end/models/extensions/ExtensionEndpoint.ts b/front_end/models/extensions/ExtensionEndpoint.ts
index 8cd071db7b..9c220fe8e1 100644
--- a/front_end/models/extensions/ExtensionEndpoint.ts
+++ b/front_end/models/extensions/ExtensionEndpoint.ts
@@ -16,7 +16,7 @@ type Message = MessageEvent<Response|Event>;
 
 export class ExtensionEndpoint {
   private readonly port: MessagePort;
-  private nextRequestId: number = 0;
+  private nextRequestId = 0;
   private pendingRequests: Map<number, {
     resolve: (arg: unknown) => void,
     reject: (error: Error) => void,
diff --git a/front_end/models/extensions/ExtensionServer.ts b/front_end/models/extensions/ExtensionServer.ts
index 76a70fa0fb..fb9a2326eb 100644
--- a/front_end/models/extensions/ExtensionServer.ts
+++ b/front_end/models/extensions/ExtensionServer.ts
@@ -919,7 +919,7 @@ export class ExtensionServer extends Common.ObjectWrapper.ObjectWrapper<EventTyp
         Logs.NetworkLog.NetworkLog.instance().requests().filter(r => this.extensionAllowedOnURL(r.url(), port));
     const harLog = await HAR.Log.Log.build(requests, {sanitize: false});
     for (let i = 0; i < harLog.entries.length; ++i) {
-      // @ts-ignore
+      // @ts-expect-error
       harLog.entries[i]._requestId = this.requestId(requests[i]);
     }
     return harLog;
@@ -1092,7 +1092,7 @@ export class ExtensionServer extends Common.ObjectWrapper.ObjectWrapper<EventTyp
         metaKey: entry.metaKey,
       });
 
-      // @ts-ignore
+      // @ts-expect-error
       event.__keyCode = keyCodeForEntry(entry);
       document.dispatchEvent(event);
     }
diff --git a/front_end/models/extensions/LanguageExtensionEndpoint.ts b/front_end/models/extensions/LanguageExtensionEndpoint.ts
index c39a5b26cb..525cbfe12a 100644
--- a/front_end/models/extensions/LanguageExtensionEndpoint.ts
+++ b/front_end/models/extensions/LanguageExtensionEndpoint.ts
@@ -151,13 +151,13 @@ export class LanguageExtensionEndpoint implements Bindings.DebuggerLanguagePlugi
   }
 
   async getMappedLines(rawModuleId: string, sourceFileURL: string): Promise<number[]|undefined> {
-    return this.endpoint.sendRequest(
+    return await this.endpoint.sendRequest(
         PrivateAPI.LanguageExtensionPluginCommands.GetMappedLines, {rawModuleId, sourceFileURL});
   }
 
   async evaluate(expression: string, context: Chrome.DevTools.RawLocation, stopId: number):
       Promise<Chrome.DevTools.RemoteObject> {
-    return this.endpoint.sendRequest(
+    return await this.endpoint.sendRequest(
         PrivateAPI.LanguageExtensionPluginCommands.FormatValue, {expression, context, stopId});
   }
 
diff --git a/front_end/models/formatter/ScriptFormatter.ts b/front_end/models/formatter/ScriptFormatter.ts
index 8694005b03..832c063f7b 100644
--- a/front_end/models/formatter/ScriptFormatter.ts
+++ b/front_end/models/formatter/ScriptFormatter.ts
@@ -61,7 +61,7 @@ export async function format(
     indent: string =
         Common.Settings.Settings.instance().moduleSetting('text-editor-indent').get()): Promise<FormattedContent> {
   if (contentType.isDocumentOrScriptOrStyleSheet()) {
-    return formatScriptContent(mimeType, content, indent);
+    return await formatScriptContent(mimeType, content, indent);
   }
 
   return {formattedContent: content, formattedMapping: new IdentityFormatterSourceMapping()};
diff --git a/front_end/models/har/HARFormat.ts b/front_end/models/har/HARFormat.ts
index 57a59d2abb..d6a5b97bb4 100644
--- a/front_end/models/har/HARFormat.ts
+++ b/front_end/models/har/HARFormat.ts
@@ -444,9 +444,9 @@ export class HARStack extends HARBase {
 export class HARCallFrame extends HARBase {
   functionName: string;
   scriptId: Protocol.Runtime.ScriptId;
-  url: string = '';
-  lineNumber: number = -1;
-  columnNumber: number = -1;
+  url = '';
+  lineNumber = -1;
+  columnNumber = -1;
   /**
    * Based on Protocol.Runtime.CallFrame defined in browser_protocol.pdl
    */
diff --git a/front_end/models/issues_manager/IssuesManager.ts b/front_end/models/issues_manager/IssuesManager.ts
index e2cfff9133..5503165707 100644
--- a/front_end/models/issues_manager/IssuesManager.ts
+++ b/front_end/models/issues_manager/IssuesManager.ts
@@ -197,7 +197,7 @@ export class IssuesManager extends Common.ObjectWrapper.ObjectWrapper<EventTypes
   #hiddenIssueCount = new Map<IssueKind, number>();
   #issuesById = new Map<string, Issue>();
   #issuesByOutermostTarget: WeakMap<SDK.Target.Target, Set<Issue>> = new Map();
-  #thirdPartyCookiePhaseoutIssueMessageSent: boolean = false;
+  #thirdPartyCookiePhaseoutIssueMessageSent = false;
 
   constructor(
       private readonly showThirdPartyIssuesSetting?: Common.Settings.Setting<boolean>,
@@ -464,7 +464,7 @@ export interface EventTypes {
   [Events.ISSUE_ADDED]: IssueAddedEvent;
 }
 
-// @ts-ignore
+// @ts-expect-error
 globalThis.addIssueForTest = (issue: Protocol.Audits.InspectorIssue) => {
   const mainTarget = SDK.TargetManager.TargetManager.instance().primaryPageTarget();
   const issuesModel = mainTarget?.model(SDK.IssuesModel.IssuesModel);
diff --git a/front_end/models/issues_manager/MarkdownIssueDescription.ts b/front_end/models/issues_manager/MarkdownIssueDescription.ts
index 2c616bd834..06e8e5f075 100644
--- a/front_end/models/issues_manager/MarkdownIssueDescription.ts
+++ b/front_end/models/issues_manager/MarkdownIssueDescription.ts
@@ -58,7 +58,7 @@ export interface IssueDescription {
 export async function getFileContent(url: URL): Promise<string> {
   try {
     const response = await fetch(url.toString());
-    return response.text();
+    return await response.text();
   } catch {
     throw new Error(
         `Markdown file ${url.toString()} not found. Make sure it is correctly listed in the relevant BUILD.gn files.`);
@@ -66,7 +66,7 @@ export async function getFileContent(url: URL): Promise<string> {
 }
 
 export async function getMarkdownFileContent(filename: string): Promise<string> {
-  return getFileContent(new URL(`descriptions/${filename}`, import.meta.url));
+  return await getFileContent(new URL(`descriptions/${filename}`, import.meta.url));
 }
 
 export async function createIssueDescriptionFromMarkdown(description: MarkdownIssueDescription):
diff --git a/front_end/models/issues_manager/RelatedIssue.ts b/front_end/models/issues_manager/RelatedIssue.ts
index 5cf9234e35..9b4f9fb2fd 100644
--- a/front_end/models/issues_manager/RelatedIssue.ts
+++ b/front_end/models/issues_manager/RelatedIssue.ts
@@ -73,12 +73,12 @@ export async function reveal(obj: IssuesAssociatable, category?: IssueCategory):
   if (typeof obj === 'string') {
     const issue = IssuesManager.instance().getIssueById(obj);
     if (issue) {
-      return Common.Revealer.reveal(issue);
+      return await Common.Revealer.reveal(issue);
     }
   }
   const issues = Array.from(IssuesManager.instance().issues());
   const candidates = issuesAssociatedWith(issues, obj).filter(issue => !category || issue.getCategory() === category);
   if (candidates.length > 0) {
-    return Common.Revealer.reveal(candidates[0]);
+    return await Common.Revealer.reveal(candidates[0]);
   }
 }
diff --git a/front_end/models/live-metrics/LiveMetrics.ts b/front_end/models/live-metrics/LiveMetrics.ts
index 43d7241424..de54416836 100644
--- a/front_end/models/live-metrics/LiveMetrics.ts
+++ b/front_end/models/live-metrics/LiveMetrics.ts
@@ -389,7 +389,7 @@ export class LiveMetrics extends Common.ObjectWrapper.ObjectWrapper<EventTypes>
     }
 
     const frameManager = SDK.FrameManager.FrameManager.instance();
-    return frameManager.getOrWaitForFrame(frameId);
+    return await frameManager.getOrWaitForFrame(frameId);
   }
 
   async #onBindingCalled(event: {data: Protocol.Runtime.BindingCalledEvent}): Promise<void> {
diff --git a/front_end/models/persistence/IsolatedFileSystem.ts b/front_end/models/persistence/IsolatedFileSystem.ts
index 9c269dabc1..9dcb27fa0f 100644
--- a/front_end/models/persistence/IsolatedFileSystem.ts
+++ b/front_end/models/persistence/IsolatedFileSystem.ts
@@ -95,7 +95,7 @@ export class IsolatedFileSystem extends PlatformFileSystem {
     }
 
     const fileSystem = new IsolatedFileSystem(manager, path, embedderPath, domFileSystem, type);
-    return fileSystem.initializeFilePaths().then(() => fileSystem).catch(error => {
+    return await fileSystem.initializeFilePaths().then(() => fileSystem).catch(error => {
       console.error(error);
       return null;
     });
@@ -381,7 +381,7 @@ export class IsolatedFileSystem extends PlatformFileSystem {
     }
 
     function errorHandler(this: IsolatedFileSystem, error: DOMError|ProgressEvent<EventTarget>): void {
-      // @ts-ignore TODO(crbug.com/1172300) Properly type this after jsdoc to ts migration
+      // @ts-expect-error TODO(crbug.com/1172300) Properly type this after jsdoc to ts migration
       const errorMessage = IsolatedFileSystem.errorMessage(error);
       console.error(errorMessage + ' when setting content for file \'' + (this.path() + '/' + path) + '\'');
       resolve(undefined);
diff --git a/front_end/models/persistence/NetworkPersistenceManager.ts b/front_end/models/persistence/NetworkPersistenceManager.ts
index 985be1ef05..9baf712a89 100644
--- a/front_end/models/persistence/NetworkPersistenceManager.ts
+++ b/front_end/models/persistence/NetworkPersistenceManager.ts
@@ -700,7 +700,7 @@ export class NetworkPersistenceManager extends Common.ObjectWrapper.ObjectWrappe
   async #innerUpdateInterceptionPatterns(): Promise<void> {
     this.#headerOverridesMap.clear();
     if (!this.activeInternal || !this.projectInternal) {
-      return SDK.NetworkManager.MultitargetNetworkManager.instance().setInterceptionHandlerForPatterns(
+      return await SDK.NetworkManager.MultitargetNetworkManager.instance().setInterceptionHandlerForPatterns(
           [], this.interceptionHandlerBound);
     }
     let patterns = new Set<string>();
@@ -730,7 +730,7 @@ export class NetworkPersistenceManager extends Common.ObjectWrapper.ObjectWrappe
       }
     }
 
-    return SDK.NetworkManager.MultitargetNetworkManager.instance().setInterceptionHandlerForPatterns(
+    return await SDK.NetworkManager.MultitargetNetworkManager.instance().setInterceptionHandlerForPatterns(
         Array.from(patterns).map(
             pattern => ({urlPattern: pattern, requestStage: Protocol.Fetch.RequestStage.Response})),
         this.interceptionHandlerBound);
diff --git a/front_end/models/persistence/PersistenceImpl.ts b/front_end/models/persistence/PersistenceImpl.ts
index 9b386fc2ae..faa857dddf 100644
--- a/front_end/models/persistence/PersistenceImpl.ts
+++ b/front_end/models/persistence/PersistenceImpl.ts
@@ -267,7 +267,7 @@ export class PersistenceImpl extends Common.ObjectWrapper.ObjectWrapper<EventTyp
         breakpointLocation => breakpointLocation.breakpoint);
     await Promise.all(breakpoints.map(async breakpoint => {
       await breakpoint.remove(false /* keepInStorage */);
-      return this.breakpointManager.setBreakpoint(
+      return await this.breakpointManager.setBreakpoint(
           to, breakpoint.lineNumber(), breakpoint.columnNumber(), breakpoint.condition(), breakpoint.enabled(),
           breakpoint.isLogpoint(), BreakpointManager.BreakpointManager.BreakpointOrigin.OTHER);
     }));
diff --git a/front_end/models/persistence/PlatformFileSystem.ts b/front_end/models/persistence/PlatformFileSystem.ts
index 937f8581c9..a0116756b5 100644
--- a/front_end/models/persistence/PlatformFileSystem.ts
+++ b/front_end/models/persistence/PlatformFileSystem.ts
@@ -50,7 +50,7 @@ export class PlatformFileSystem {
 
   async createFile(_path: Platform.DevToolsPath.EncodedPathString, _name: Platform.DevToolsPath.RawPathString|null):
       Promise<Platform.DevToolsPath.EncodedPathString|null> {
-    return Promise.resolve(null);
+    return await Promise.resolve(null);
   }
 
   deleteFile(_path: Platform.DevToolsPath.EncodedPathString): Promise<boolean> {
diff --git a/front_end/models/source_map_scopes/NamesResolver.ts b/front_end/models/source_map_scopes/NamesResolver.ts
index 9bd1731ea0..cd22c7c554 100644
--- a/front_end/models/source_map_scopes/NamesResolver.ts
+++ b/front_end/models/source_map_scopes/NamesResolver.ts
@@ -208,7 +208,7 @@ const resolveDebuggerScope = async(scope: SDK.DebuggerModel.ScopeChainEntry):
       }
       const script = scope.callFrame().script;
       const scopeChain = await findScopeChainForDebuggerScope(scope);
-      return resolveScope(script, scopeChain);
+      return await resolveScope(script, scopeChain);
     };
 
 const resolveScope = async(script: SDK.Script.Script, scopeChain: Formatter.FormatterWorkerPool.ScopeTreeNode[]):
@@ -727,11 +727,11 @@ export class RemoteObject extends SDK.RemoteObject.RemoteObject {
         break;
       }
     }
-    return this.object.setPropertyValue(actualName, value);
+    return await this.object.setPropertyValue(actualName, value);
   }
 
   override async deleteProperty(name: Protocol.Runtime.CallArgument): Promise<string|undefined> {
-    return this.object.deleteProperty(name);
+    return await this.object.deleteProperty(name);
   }
 
   override callFunction<T, U>(
diff --git a/front_end/models/source_map_scopes/ScopeChainModel.test.ts b/front_end/models/source_map_scopes/ScopeChainModel.test.ts
index dfffe4fa9a..59612fefe1 100644
--- a/front_end/models/source_map_scopes/ScopeChainModel.test.ts
+++ b/front_end/models/source_map_scopes/ScopeChainModel.test.ts
@@ -41,7 +41,7 @@ describeWithMockConnection('ScopeChainModel', () => {
     const debuggerModel = target.model(SDK.DebuggerModel.DebuggerModel)!;
     const fakeFrame = sinon.createStubInstance(SDK.DebuggerModel.CallFrame);
     fakeFrame.debuggerModel = debuggerModel;
-    // @ts-ignore readonly for test.
+    // @ts-expect-error readonly for test.
     fakeFrame.script = sinon.createStubInstance(SDK.Script.Script, {isWasm: false});
     fakeFrame.scopeChain.returns([]);
 
@@ -63,7 +63,7 @@ describeWithMockConnection('ScopeChainModel', () => {
     const debuggerModel = target.model(SDK.DebuggerModel.DebuggerModel)!;
     const fakeFrame = sinon.createStubInstance(SDK.DebuggerModel.CallFrame);
     fakeFrame.debuggerModel = debuggerModel;
-    // @ts-ignore readonly for test.
+    // @ts-expect-error readonly for test.
     fakeFrame.script = sinon.createStubInstance(SDK.Script.Script, {isWasm: false});
 
     fakeFrame.scopeChain.returns([]);
diff --git a/front_end/models/text_utils/ContentProvider.ts b/front_end/models/text_utils/ContentProvider.ts
index c92e53f52e..d13bbacb07 100644
--- a/front_end/models/text_utils/ContentProvider.ts
+++ b/front_end/models/text_utils/ContentProvider.ts
@@ -57,7 +57,7 @@ export class SearchMatch {
 
 export const contentAsDataURL = function(
     content: string|null, mimeType: string, contentEncoded: boolean, charset?: string|null,
-    limitSize: boolean = true): string|null {
+    limitSize = true): string|null {
   const maxDataUrlSize = 1024 * 1024;
   if (content === undefined || content === null || (limitSize && content.length > maxDataUrlSize)) {
     return null;
diff --git a/front_end/models/text_utils/TextCursor.ts b/front_end/models/text_utils/TextCursor.ts
index b66c8adcbb..43af28ac9a 100644
--- a/front_end/models/text_utils/TextCursor.ts
+++ b/front_end/models/text_utils/TextCursor.ts
@@ -7,9 +7,9 @@ import * as Platform from '../../core/platform/platform.js';
 export class TextCursor {
   readonly #lineEndings: number[];
 
-  #offset: number = 0;
-  #lineNumber: number = 0;
-  #columnNumber: number = 0;
+  #offset = 0;
+  #lineNumber = 0;
+  #columnNumber = 0;
 
   constructor(lineEndings: number[]) {
     this.#lineEndings = lineEndings;
diff --git a/front_end/models/trace/extras/FetchNodes.ts b/front_end/models/trace/extras/FetchNodes.ts
index 59730bf38b..f238ef0896 100644
--- a/front_end/models/trace/extras/FetchNodes.ts
+++ b/front_end/models/trace/extras/FetchNodes.ts
@@ -112,7 +112,7 @@ export async function extractRelatedDOMNodesFromEvent(modelData: Handlers.Types.
     Promise<Map<Protocol.DOM.BackendNodeId, SDK.DOMModel.DOMNode|null>|null> {
   const nodeIds = nodeIdsForEvent(modelData, event);
   if (nodeIds.size) {
-    return domNodesForMultipleBackendNodeIds(modelData, Array.from(nodeIds));
+    return await domNodesForMultipleBackendNodeIds(modelData, Array.from(nodeIds));
   }
   return null;
 }
diff --git a/front_end/models/trace/extras/StackTraceForEvent.test.ts b/front_end/models/trace/extras/StackTraceForEvent.test.ts
index 68efc3ab1e..a18004b9ae 100644
--- a/front_end/models/trace/extras/StackTraceForEvent.test.ts
+++ b/front_end/models/trace/extras/StackTraceForEvent.test.ts
@@ -12,7 +12,7 @@ function shapeStackTraceAsArray(stackTrace: Protocol.Runtime.StackTrace):
   const stackTraceAsArray: Array<{callFrames: Protocol.Runtime.CallFrame[], description?: string}> = [];
   let currentStackTrace: Protocol.Runtime.StackTrace|undefined = stackTrace;
   while (currentStackTrace) {
-    // @ts-ignore `codeType` is not included in the protocol types but
+    // @ts-expect-error `codeType` is not included in the protocol types but
     // occasionally present
     currentStackTrace.callFrames.forEach(callFrame => delete callFrame.codeType);
     stackTraceAsArray.push({callFrames: currentStackTrace.callFrames, description: currentStackTrace.description});
diff --git a/front_end/models/trace/handlers/ExtensionTraceDataHandler.test.ts b/front_end/models/trace/handlers/ExtensionTraceDataHandler.test.ts
index 088c46db1a..9d7b322193 100644
--- a/front_end/models/trace/handlers/ExtensionTraceDataHandler.test.ts
+++ b/front_end/models/trace/handlers/ExtensionTraceDataHandler.test.ts
@@ -82,13 +82,13 @@ export async function createTraceExtensionDataFromPerformanceAPITestInput(
     extensionData: PerformanceAPIExtensionTestData[]):
     Promise<Trace.Handlers.ModelHandlers.ExtensionTraceData.ExtensionTraceData> {
   const events = extensionData.flatMap(makeTimingEventWithPerformanceExtensionData).sort((e1, e2) => e1.ts - e2.ts);
-  return createTraceExtensionDataFromEvents(events);
+  return await createTraceExtensionDataFromEvents(events);
 }
 
 async function createTraceExtensionDataFromConsoleAPITestInput(extensionData: ConsoleAPIExtensionTestData[]):
     Promise<Trace.Handlers.ModelHandlers.ExtensionTraceData.ExtensionTraceData> {
   const events = extensionData.flatMap(makeTimingEventWithConsoleExtensionData).sort((e1, e2) => e1.ts - e2.ts);
-  return createTraceExtensionDataFromEvents(events);
+  return await createTraceExtensionDataFromEvents(events);
 }
 
 async function createTraceExtensionDataFromEvents(events: Trace.Types.Events.Event[]):
diff --git a/front_end/models/trace/handlers/FramesHandler.ts b/front_end/models/trace/handlers/FramesHandler.ts
index 66d07a520d..1db66f8d21 100644
--- a/front_end/models/trace/handlers/FramesHandler.ts
+++ b/front_end/models/trace/handlers/FramesHandler.ts
@@ -391,7 +391,7 @@ class TimelineFrame implements Types.Events.LegacyTimelineFrame {
   pid = Types.Events.ProcessID(-1);
   tid = Types.Events.ThreadID(-1);
 
-  index: number = -1;
+  index = -1;
   startTime: Types.Timing.Micro;
   startTimeOffset: Types.Timing.Micro;
   endTime: Types.Timing.Micro;
diff --git a/front_end/models/trace/handlers/LayoutShiftsHandler.ts b/front_end/models/trace/handlers/LayoutShiftsHandler.ts
index fb1dd0a74a..1a6e5bade7 100644
--- a/front_end/models/trace/handlers/LayoutShiftsHandler.ts
+++ b/front_end/models/trace/handlers/LayoutShiftsHandler.ts
@@ -417,7 +417,7 @@ async function buildLayoutShiftsClusters(): Promise<void> {
       updateTraceWindowMax(cluster.clusterWindow, Types.Timing.Micro(clusterEnd));
     }
 
-    let largestScore: number = 0;
+    let largestScore = 0;
     let worstShiftEvent: Types.Events.Event|null = null;
 
     for (const shift of cluster.events) {
diff --git a/front_end/models/trace/handlers/MetaHandler.ts b/front_end/models/trace/handlers/MetaHandler.ts
index a94b81ea63..d33d149e3b 100644
--- a/front_end/models/trace/handlers/MetaHandler.ts
+++ b/front_end/models/trace/handlers/MetaHandler.ts
@@ -11,8 +11,8 @@ const rendererProcessesByFrameId: FrameProcessData = new Map();
 
 // We will often want to key data by Frame IDs, and commonly we'll care most
 // about the main frame's ID, so we store and expose that.
-let mainFrameId: string = '';
-let mainFrameURL: string = '';
+let mainFrameId = '';
+let mainFrameURL = '';
 
 const framesByProcessId = new Map<Types.Events.ProcessID, Map<string, Types.Events.TraceFrame>>();
 
diff --git a/front_end/models/trace/lantern/simulation/Simulator.test.ts b/front_end/models/trace/lantern/simulation/Simulator.test.ts
index 88a10909be..c513721cec 100644
--- a/front_end/models/trace/lantern/simulation/Simulator.test.ts
+++ b/front_end/models/trace/lantern/simulation/Simulator.test.ts
@@ -76,7 +76,7 @@ function cpuTask({tid, ts, duration}: {
 
 describe('DependencyGraph/Simulator', () => {
   // Insulate the simulator tests from DNS multiplier changes
-  let originalDNSMultiplier: number = 1;
+  let originalDNSMultiplier = 1;
   let trace: Lantern.Types.Trace;
 
   before(async function() {
diff --git a/front_end/models/workspace/UISourceCode.ts b/front_end/models/workspace/UISourceCode.ts
index 7c845697dd..047a55a08e 100644
--- a/front_end/models/workspace/UISourceCode.ts
+++ b/front_end/models/workspace/UISourceCode.ts
@@ -577,13 +577,13 @@ export class UILocation {
     this.columnNumber = columnNumber;
   }
 
-  linkText(skipTrim: boolean = false, showColumnNumber: boolean = false): string {
+  linkText(skipTrim = false, showColumnNumber = false): string {
     const displayName = this.uiSourceCode.displayName(skipTrim);
     const lineAndColumnText = this.lineAndColumnText(showColumnNumber);
     return lineAndColumnText ? displayName + ':' + lineAndColumnText : displayName;
   }
 
-  lineAndColumnText(showColumnNumber: boolean = false): string|undefined {
+  lineAndColumnText(showColumnNumber = false): string|undefined {
     let lineAndColumnText;
     if (this.uiSourceCode.mimeType() === 'application/wasm') {
       // For WebAssembly locations, we follow the conventions described in
diff --git a/front_end/models/workspace_diff/WorkspaceDiff.ts b/front_end/models/workspace_diff/WorkspaceDiff.ts
index 43b517c344..85943cbfb3 100644
--- a/front_end/models/workspace_diff/WorkspaceDiff.ts
+++ b/front_end/models/workspace_diff/WorkspaceDiff.ts
@@ -241,7 +241,7 @@ export class UISourceCodeDiff extends Common.ObjectWrapper.ObjectWrapper<UISourc
         Persistence.NetworkPersistenceManager.NetworkPersistenceManager.instance().originalContentForUISourceCode(
             this.uiSourceCode);
     if (originalNetworkContent) {
-      return originalNetworkContent;
+      return await originalNetworkContent;
     }
 
     const content = await this.uiSourceCode.project().requestFileContent(this.uiSourceCode);
diff --git a/front_end/panels/accessibility/AccessibilityNodeView.ts b/front_end/panels/accessibility/AccessibilityNodeView.ts
index 55e2c36ac5..aec970a545 100644
--- a/front_end/panels/accessibility/AccessibilityNodeView.ts
+++ b/front_end/panels/accessibility/AccessibilityNodeView.ts
@@ -272,7 +272,7 @@ export class AXNodePropertyTreeElement extends UI.TreeOutline.TreeElement {
   appendNameElement(name: string): void {
     const nameElement = document.createElement('span');
     if (name in AXAttributes) {
-      // @ts-ignore TS can't cast name here but we checked it's valid.
+      // @ts-expect-error TS can't cast name here but we checked it's valid.
       const attribute = AXAttributes[name];
       nameElement.textContent = attribute.name();
       UI.Tooltip.Tooltip.install(nameElement, attribute.description());
diff --git a/front_end/panels/ai_assistance/AiAssistancePanel.ts b/front_end/panels/ai_assistance/AiAssistancePanel.ts
index 7123b24d07..a7f1fed0f0 100644
--- a/front_end/panels/ai_assistance/AiAssistancePanel.ts
+++ b/front_end/panels/ai_assistance/AiAssistancePanel.ts
@@ -302,9 +302,9 @@ export class AiAssistancePanel extends UI.Panel.Panel {
   // Indicates whether the new conversation context is blocked due to cross-origin restrictions.
   // This happens when the conversation's context has a different
   // origin than the selected context.
-  #blockedByCrossOrigin: boolean = false;
+  #blockedByCrossOrigin = false;
   // Whether the UI should show loading or not.
-  #isLoading: boolean = false;
+  #isLoading = false;
   // Selected conversation context. The reason we keep this as a
   // state field rather than using `#getConversationContext` is that,
   // there is a case where the context differs from the selectedElement (or other selected context type).
@@ -321,7 +321,7 @@ export class AiAssistancePanel extends UI.Panel.Panel {
   #project?: Workspace.Workspace.Project;
   #patchSuggestion?: string;
   #patchSuggestionLoading?: boolean;
-  #imageInput: string = '';
+  #imageInput = '';
   #workspace = Workspace.Workspace.WorkspaceImpl.instance();
 
   constructor(private view: View = defaultView, {aidaClient, aidaAvailability, syncInfo}: {
diff --git a/front_end/panels/ai_assistance/EvaluateAction.test.ts b/front_end/panels/ai_assistance/EvaluateAction.test.ts
index a4d81886c2..f44b328159 100644
--- a/front_end/panels/ai_assistance/EvaluateAction.test.ts
+++ b/front_end/panels/ai_assistance/EvaluateAction.test.ts
@@ -88,7 +88,7 @@ describe('FreestylerEvaluateAction', () => {
       const targetManager = SDK.TargetManager.TargetManager.instance();
       const target = targetManager.rootTarget();
       const runtimeModel = target!.model(SDK.RuntimeModel.RuntimeModel);
-      return getExecutionContext(runtimeModel!);
+      return await getExecutionContext(runtimeModel!);
     }
 
     async function executeForTest(action: string, throwOnSideEffect = false) {
@@ -101,7 +101,7 @@ describe('FreestylerEvaluateAction', () => {
     return error;
   }
 }`;
-      return EvaluateAction.EvaluateAction.execute(
+      return await EvaluateAction.EvaluateAction.execute(
           functionDeclaration, [], await executionContextForTest(), {throwOnSideEffect});
     }
 
diff --git a/front_end/panels/ai_assistance/EvaluateAction.ts b/front_end/panels/ai_assistance/EvaluateAction.ts
index 52549af3ad..2d554d1353 100644
--- a/front_end/panels/ai_assistance/EvaluateAction.ts
+++ b/front_end/panels/ai_assistance/EvaluateAction.ts
@@ -111,7 +111,7 @@ export class EvaluateAction {
         return formatError(exceptionDescription ?? 'JS exception');
       }
 
-      return stringifyRemoteObject(response.object);
+      return await stringifyRemoteObject(response.object);
     } finally {
       executionContext.runtimeModel.releaseEvaluationResult(response);
     }
diff --git a/front_end/panels/ai_assistance/agents/StylingAgent.ts b/front_end/panels/ai_assistance/agents/StylingAgent.ts
index 949e0433f9..eca5c573a7 100644
--- a/front_end/panels/ai_assistance/agents/StylingAgent.ts
+++ b/front_end/panels/ai_assistance/agents/StylingAgent.ts
@@ -836,7 +836,7 @@ Please run ACTION again if the information you received is not enough to answer
           params,
           options,
           ) => {
-        return this.executeAction(params.action, options);
+        return await this.executeAction(params.action, options);
       },
     });
 
diff --git a/front_end/panels/ai_assistance/ai_assistance-meta.ts b/front_end/panels/ai_assistance/ai_assistance-meta.ts
index caa1392ab6..651a54d98f 100644
--- a/front_end/panels/ai_assistance/ai_assistance-meta.ts
+++ b/front_end/panels/ai_assistance/ai_assistance-meta.ts
@@ -114,7 +114,7 @@ UI.ViewManager.registerViewExtension({
   condition: config => isAnyFeatureAvailable(config) && !isPolicyRestricted(config),
   async loadView() {
     const AiAssistance = await loadAiAssistanceModule();
-    return AiAssistance.AiAssistancePanel.instance();
+    return await AiAssistance.AiAssistancePanel.instance();
   },
 });
 
diff --git a/front_end/panels/ai_assistance/components/ChatView.ts b/front_end/panels/ai_assistance/components/ChatView.ts
index 6635121a86..01e3f94245 100644
--- a/front_end/panels/ai_assistance/components/ChatView.ts
+++ b/front_end/panels/ai_assistance/components/ChatView.ts
@@ -973,7 +973,7 @@ function renderStepBadge({step, isLoading, isLast}: {
     return html`<devtools-spinner></devtools-spinner>`;
   }
 
-  let iconName: string = 'checkmark';
+  let iconName = 'checkmark';
   let ariaLabel: string|undefined = lockedString(UIStringsNotTranslate.completed);
   let role: 'button'|undefined = 'button';
   if (isLast && step.sideEffect) {
diff --git a/front_end/panels/ai_assistance/components/MarkdownRendererWithCodeBlock.ts b/front_end/panels/ai_assistance/components/MarkdownRendererWithCodeBlock.ts
index 3d757e407e..3000ad350e 100644
--- a/front_end/panels/ai_assistance/components/MarkdownRendererWithCodeBlock.ts
+++ b/front_end/panels/ai_assistance/components/MarkdownRendererWithCodeBlock.ts
@@ -17,7 +17,7 @@ import type * as Lit from '../../../ui/lit/lit.js';
 // }
 // ```
 export class MarkdownRendererWithCodeBlock extends MarkdownView.MarkdownView.MarkdownInsightRenderer {
-  #stripLinks: boolean = false;
+  #stripLinks = false;
   constructor(opts: {stripLinks?: boolean} = {}) {
     super();
     this.#stripLinks = Boolean(opts.stripLinks);
diff --git a/front_end/panels/ai_assistance/debug.ts b/front_end/panels/ai_assistance/debug.ts
index bff1f7c076..fbe0a3cc5d 100644
--- a/front_end/panels/ai_assistance/debug.ts
+++ b/front_end/panels/ai_assistance/debug.ts
@@ -26,5 +26,5 @@ function setDebugAiAssistanceEnabled(enabled: boolean): void {
     localStorage.removeItem('debugAiAssistancePanelEnabled');
   }
 }
-// @ts-ignore
+// @ts-expect-error
 globalThis.setDebugAiAssistanceEnabled = setDebugAiAssistanceEnabled;
diff --git a/front_end/panels/animation/AnimationTimeline.ts b/front_end/panels/animation/AnimationTimeline.ts
index e05612c677..6136da9ab1 100644
--- a/front_end/panels/animation/AnimationTimeline.ts
+++ b/front_end/panels/animation/AnimationTimeline.ts
@@ -282,7 +282,7 @@ export class AnimationTimeline extends UI.Widget.VBox implements
     }
 
     this.#showPanelInDrawer();
-    return this.selectAnimationGroup(animationGroup);
+    return await this.selectAnimationGroup(animationGroup);
   }
 
   modelAdded(animationModel: SDK.AnimationModel.AnimationModel): void {
@@ -1122,9 +1122,9 @@ export class AnimationTimeline extends UI.Widget.VBox implements
     }
 
     if (this.#selectedGroup?.scrollOrientation() === Protocol.DOM.ScrollOrientation.Vertical) {
-      return node.setScrollTop(offset);
+      return await node.setScrollTop(offset);
     }
-    return node.setScrollLeft(offset);
+    return await node.setScrollLeft(offset);
   }
 
   private setTimelineScrubberPosition(time: number): void {
diff --git a/front_end/panels/application/ApplicationPanelSidebar.test.ts b/front_end/panels/application/ApplicationPanelSidebar.test.ts
index c79a668e67..4d44a59c5d 100644
--- a/front_end/panels/application/ApplicationPanelSidebar.test.ts
+++ b/front_end/panels/application/ApplicationPanelSidebar.test.ts
@@ -281,7 +281,7 @@ describeWithMockConnection('ApplicationPanelSidebar', () => {
     const sidebar = await Application.ResourcesPanel.ResourcesPanel.showAndGetSidebar();
     const components = expectedCall.split('.');
     assert.lengthOf(components, 2);
-    // @ts-ignore
+    // @ts-expect-error
     const object = sidebar[components[0]];
     assert.exists(object);
     return sinon.spy(object, components[1]);
diff --git a/front_end/panels/application/ApplicationPanelSidebar.ts b/front_end/panels/application/ApplicationPanelSidebar.ts
index a05f10edaf..9bb4286221 100644
--- a/front_end/panels/application/ApplicationPanelSidebar.ts
+++ b/front_end/panels/application/ApplicationPanelSidebar.ts
@@ -568,8 +568,6 @@ export class ApplicationPanelSidebar extends UI.Widget.VBox implements SDK.Targe
     this.sharedStorageTreeElementDispatcher =
         new Common.ObjectWrapper.ObjectWrapper<SharedStorageTreeElementDispatcher.EventTypes>();
 
-    // Work-around for crbug.com/1152713: Something is wrong with custom scrollbars and size containment.
-    // @ts-ignore
     this.contentElement.style.contain = 'layout style';
   }
 
diff --git a/front_end/panels/application/CookieItemsView.ts b/front_end/panels/application/CookieItemsView.ts
index dd51293152..e60c70a419 100644
--- a/front_end/panels/application/CookieItemsView.ts
+++ b/front_end/panels/application/CookieItemsView.ts
@@ -256,7 +256,7 @@ export class CookieItemsView extends StorageItemsView {
     if (oldCookie && newCookie.key() !== oldCookie.key()) {
       await this.model.deleteCookie(oldCookie);
     }
-    return this.model.saveCookie(newCookie);
+    return await this.model.saveCookie(newCookie);
   }
 
   private deleteCookie(cookie: SDK.Cookie.Cookie, callback: () => void): void {
diff --git a/front_end/panels/application/ExtensionStorageItemsView.test.ts b/front_end/panels/application/ExtensionStorageItemsView.test.ts
index 6ce44f9362..b85e3d0c3f 100644
--- a/front_end/panels/application/ExtensionStorageItemsView.test.ts
+++ b/front_end/panels/application/ExtensionStorageItemsView.test.ts
@@ -18,8 +18,8 @@ import View = Resources.ExtensionStorageItemsView;
 
 class ExtensionStorageItemsListener {
   #dispatcher: Common.ObjectWrapper.ObjectWrapper<View.ExtensionStorageItemsDispatcher.EventTypes>;
-  #edited: boolean = false;
-  #refreshed: boolean = false;
+  #edited = false;
+  #refreshed = false;
 
   constructor(dispatcher: Common.ObjectWrapper.ObjectWrapper<View.ExtensionStorageItemsDispatcher.EventTypes>) {
     this.#dispatcher = dispatcher;
diff --git a/front_end/panels/application/ServiceWorkerCacheViews.ts b/front_end/panels/application/ServiceWorkerCacheViews.ts
index 56de4db300..6238a896cf 100644
--- a/front_end/panels/application/ServiceWorkerCacheViews.ts
+++ b/front_end/panels/application/ServiceWorkerCacheViews.ts
@@ -360,12 +360,12 @@ export class ServiceWorkerCacheView extends UI.View.SimpleView {
     returnCount: number,
   }|undefined> {
     if (!force && this.loadingPromise) {
-      return this.loadingPromise;
+      return await this.loadingPromise;
     }
     this.refreshButton.setEnabled(false);
 
     if (this.loadingPromise) {
-      return this.loadingPromise;
+      return await this.loadingPromise;
     }
 
     this.loadingPromise = new Promise(resolve => {
diff --git a/front_end/panels/application/ServiceWorkerUpdateCycleView.ts b/front_end/panels/application/ServiceWorkerUpdateCycleView.ts
index e42d04177e..04f06f12fe 100644
--- a/front_end/panels/application/ServiceWorkerUpdateCycleView.ts
+++ b/front_end/panels/application/ServiceWorkerUpdateCycleView.ts
@@ -78,10 +78,10 @@ export class ServiceWorkerUpdateCycleView {
 
     function rangesForVersion(version: SDK.ServiceWorkerManager.ServiceWorkerVersion): ServiceWorkerUpdateRange[] {
       let state: SDK.ServiceWorkerManager.ServiceWorkerVersionState|null = version.currentState;
-      let endActivateTime: number = 0;
-      let beginActivateTime: number = 0;
-      let endInstallTime: number = 0;
-      let beginInstallTime: number = 0;
+      let endActivateTime = 0;
+      let beginActivateTime = 0;
+      let endInstallTime = 0;
+      let beginInstallTime = 0;
       const currentStatus = state.status;
       if (currentStatus === Protocol.ServiceWorker.ServiceWorkerVersionStatus.New) {
         return [];
diff --git a/front_end/panels/application/ServiceWorkersView.ts b/front_end/panels/application/ServiceWorkersView.ts
index 82ccf95f76..fcc6e2bd0a 100644
--- a/front_end/panels/application/ServiceWorkersView.ts
+++ b/front_end/panels/application/ServiceWorkersView.ts
@@ -262,7 +262,7 @@ export class ServiceWorkersView extends UI.Widget.VBox implements
     this.updateListVisibility();
 
     const drawerChangeHandler = (event: Event): void => {
-      // @ts-ignore: No support for custom event listener
+      // @ts-expect-error: No support for custom event listener
       const isDrawerOpen = event.detail && event.detail.isDrawerOpen;
       if (this.manager && !isDrawerOpen) {
         const {serviceWorkerNetworkRequestsPanelStatus: {isOpen, openedAt}} = this.manager;
diff --git a/front_end/panels/application/SharedStorageItemsView.test.ts b/front_end/panels/application/SharedStorageItemsView.test.ts
index aba20ea94c..5cc2fb2167 100644
--- a/front_end/panels/application/SharedStorageItemsView.test.ts
+++ b/front_end/panels/application/SharedStorageItemsView.test.ts
@@ -23,9 +23,9 @@ import View = Resources.SharedStorageItemsView;
 
 class SharedStorageItemsListener {
   #dispatcher: Common.ObjectWrapper.ObjectWrapper<View.SharedStorageItemsDispatcher.EventTypes>;
-  #cleared: boolean = false;
-  #filteredCleared: boolean = false;
-  #refreshed: boolean = false;
+  #cleared = false;
+  #filteredCleared = false;
+  #refreshed = false;
   #deletedKeys: String[] = [];
   #numEditedEvents = 0;
 
diff --git a/front_end/panels/application/SharedStorageModel.ts b/front_end/panels/application/SharedStorageModel.ts
index c18c713bc5..b494b9ca47 100644
--- a/front_end/panels/application/SharedStorageModel.ts
+++ b/front_end/panels/application/SharedStorageModel.ts
@@ -22,12 +22,12 @@ export class SharedStorageForOrigin extends Common.ObjectWrapper.ObjectWrapper<S
   }
 
   async getMetadata(): Promise<Protocol.Storage.SharedStorageMetadata|null> {
-    return this.#model.storageAgent.invoke_getSharedStorageMetadata({ownerOrigin: this.securityOrigin})
+    return await this.#model.storageAgent.invoke_getSharedStorageMetadata({ownerOrigin: this.securityOrigin})
         .then(({metadata}) => metadata);
   }
 
   async getEntries(): Promise<Protocol.Storage.SharedStorageEntry[]|null> {
-    return this.#model.storageAgent.invoke_getSharedStorageEntries({ownerOrigin: this.securityOrigin})
+    return await this.#model.storageAgent.invoke_getSharedStorageEntries({ownerOrigin: this.securityOrigin})
         .then(({entries}) => entries);
   }
 
diff --git a/front_end/panels/application/SharedStorageTreeElement.test.ts b/front_end/panels/application/SharedStorageTreeElement.test.ts
index ba1cab88b9..25922a43bb 100644
--- a/front_end/panels/application/SharedStorageTreeElement.test.ts
+++ b/front_end/panels/application/SharedStorageTreeElement.test.ts
@@ -19,7 +19,7 @@ import * as Application from './application.js';
 class SharedStorageItemsListener {
   #dispatcher:
       Common.ObjectWrapper.ObjectWrapper<Application.SharedStorageItemsView.SharedStorageItemsDispatcher.EventTypes>;
-  #refreshed: boolean = false;
+  #refreshed = false;
 
   constructor(dispatcher: Common.ObjectWrapper
                   .ObjectWrapper<Application.SharedStorageItemsView.SharedStorageItemsDispatcher.EventTypes>) {
diff --git a/front_end/panels/application/components/ProtocolHandlersView.ts b/front_end/panels/application/components/ProtocolHandlersView.ts
index 2623024b7c..e9f4af26a6 100644
--- a/front_end/panels/application/components/ProtocolHandlersView.ts
+++ b/front_end/panels/application/components/ProtocolHandlersView.ts
@@ -96,8 +96,8 @@ export class ProtocolHandlersView extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   #protocolHandlers: ProtocolHandler[] = [];
   #manifestLink: Platform.DevToolsPath.UrlString = Platform.DevToolsPath.EmptyUrlString;
-  #selectedProtocolState: string = '';
-  #queryInputState: string = '';
+  #selectedProtocolState = '';
+  #queryInputState = '';
 
   set data(data: ProtocolHandlersData) {
     const isNewManifest = this.#manifestLink !== data.manifestLink;
diff --git a/front_end/panels/application/components/SharedStorageMetadataView.ts b/front_end/panels/application/components/SharedStorageMetadataView.ts
index 9d7b81e8c8..d4442abc3f 100644
--- a/front_end/panels/application/components/SharedStorageMetadataView.ts
+++ b/front_end/panels/application/components/SharedStorageMetadataView.ts
@@ -63,9 +63,9 @@ interface SharedStorageMetadataGetter {
 export class SharedStorageMetadataView extends StorageMetadataView {
   #sharedStorageMetadataGetter: SharedStorageMetadataGetter;
   #creationTime: Protocol.Network.TimeSinceEpoch|null = null;
-  #length: number = 0;
-  #bytesUsed: number = 0;
-  #remainingBudget: number = 0;
+  #length = 0;
+  #bytesUsed = 0;
+  #remainingBudget = 0;
 
   constructor(sharedStorageMetadataGetter: SharedStorageMetadataGetter, owner: string) {
     super();
diff --git a/front_end/panels/application/components/StackTrace.ts b/front_end/panels/application/components/StackTrace.ts
index 0121164ffa..298e2d8765 100644
--- a/front_end/panels/application/components/StackTrace.ts
+++ b/front_end/panels/application/components/StackTrace.ts
@@ -108,7 +108,7 @@ export class StackTraceLinkButton extends HTMLElement {
 
   #onShowAllClick: () => void = () => {};
   #hiddenCallFramesCount: number|null = null;
-  #expandedView: boolean = false;
+  #expandedView = false;
 
   set data(data: StackTraceLinkButtonData) {
     this.#onShowAllClick = data.onShowAllClick;
diff --git a/front_end/panels/application/preloading/PreloadingView.test.ts b/front_end/panels/application/preloading/PreloadingView.test.ts
index fb3e8ac855..cde5ce036c 100644
--- a/front_end/panels/application/preloading/PreloadingView.test.ts
+++ b/front_end/panels/application/preloading/PreloadingView.test.ts
@@ -28,7 +28,7 @@ const zip2 = <T, S>(xs: T[], ys: S[]) => {
 
 // Holds targets and ids, and emits events.
 class NavigationEmulator {
-  private seq: number = 0;
+  private seq = 0;
   private tabTarget: SDK.Target.Target;
   primaryTarget: SDK.Target.Target;
   private frameId: Protocol.Page.FrameId;
diff --git a/front_end/panels/application/preloading/PreloadingView.ts b/front_end/panels/application/preloading/PreloadingView.ts
index c0e3b77d0c..6bd0dde913 100644
--- a/front_end/panels/application/preloading/PreloadingView.ts
+++ b/front_end/panels/application/preloading/PreloadingView.ts
@@ -84,7 +84,7 @@ const str_ = i18n.i18n.registerUIStrings('panels/application/preloading/Preloadi
 const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
 
 // Used for selector, indicating no filter is specified.
-const AllRuleSetRootId: symbol = Symbol('AllRuleSetRootId');
+const AllRuleSetRootId = Symbol('AllRuleSetRootId');
 
 class PreloadingUIUtils {
   static status(status: SDK.PreloadingModel.PreloadingStatus): string {
@@ -581,7 +581,7 @@ class PreloadingRuleSetSelector implements
 
   private onModelUpdated(): void {
     const ids = this.model.getAllRuleSets().map(({id}) => id);
-    const items = [AllRuleSetRootId, ...ids];
+    const items = [AllRuleSetRootId, ...ids] as [typeof AllRuleSetRootId, ...Protocol.Preload.RuleSetId[]];
     const selected = this.dropDown.getSelectedItem();
     this.listModel.replaceAll(items);
     if (selected === null) {
diff --git a/front_end/panels/application/preloading/components/RuleSetDetailsView.ts b/front_end/panels/application/preloading/components/RuleSetDetailsView.ts
index e155624b81..f4ade0c6df 100644
--- a/front_end/panels/application/preloading/components/RuleSetDetailsView.ts
+++ b/front_end/panels/application/preloading/components/RuleSetDetailsView.ts
@@ -31,7 +31,7 @@ export type RuleSetDetailsViewData = RuleSet|null;
 export class RuleSetDetailsView extends LegacyWrapper.LegacyWrapper.WrappableComponent<UI.Widget.VBox> {
   readonly #shadow = this.attachShadow({mode: 'open'});
   #data: RuleSetDetailsViewData = null;
-  #shouldPrettyPrint: boolean = true;
+  #shouldPrettyPrint = true;
   #editorState?: CodeMirror.EditorState;
 
   connectedCallback(): void {
diff --git a/front_end/panels/autofill/AutofillView.ts b/front_end/panels/autofill/AutofillView.ts
index e7b6c24286..930f37659e 100644
--- a/front_end/panels/autofill/AutofillView.ts
+++ b/front_end/panels/autofill/AutofillView.ts
@@ -120,7 +120,7 @@ export class AutofillView extends LegacyWrapper.LegacyWrapper.WrappableComponent
   readonly #renderBound = this.#render.bind(this);
   #autoOpenViewSetting: Common.Settings.Setting<boolean>;
   #showTestAddressesInAutofillMenuSetting: Common.Settings.Setting<boolean>;
-  #address: string = '';
+  #address = '';
   #filledFields: Protocol.Autofill.FilledField[] = [];
   #matches: AutofillManager.AutofillManager.Match[] = [];
   #highlightedMatches: AutofillManager.AutofillManager.Match[] = [];
diff --git a/front_end/panels/changes/ChangesSidebar.ts b/front_end/panels/changes/ChangesSidebar.ts
index 68d29c96b2..1dbdabc418 100644
--- a/front_end/panels/changes/ChangesSidebar.ts
+++ b/front_end/panels/changes/ChangesSidebar.ts
@@ -50,7 +50,7 @@ export class ChangesSidebar extends Common.ObjectWrapper.eventMixin<EventTypes,
   }
 
   selectedUISourceCode(): Workspace.UISourceCode.UISourceCode|null {
-    // @ts-ignore uiSourceCode seems to be dynamically attached.
+    // @ts-expect-error uiSourceCode seems to be dynamically attached.
     return this.treeoutline.selectedTreeElement ? this.treeoutline.selectedTreeElement.uiSourceCode : null;
   }
 
diff --git a/front_end/panels/console/ConsoleView.ts b/front_end/panels/console/ConsoleView.ts
index 1cccecc490..1a2b713e31 100644
--- a/front_end/panels/console/ConsoleView.ts
+++ b/front_end/panels/console/ConsoleView.ts
@@ -323,7 +323,7 @@ export class ConsoleView extends UI.Widget.VBox implements
   private issueToolbarThrottle: Common.Throttler.Throttler;
   private requestResolver = new Logs.RequestResolver.RequestResolver();
   private issueResolver = new IssuesManager.IssueResolver.IssueResolver();
-  #isDetached: boolean = false;
+  #isDetached = false;
   #onIssuesCountUpdateBound = this.#onIssuesCountUpdate.bind(this);
 
   constructor(viewportThrottlerTimeout: number) {
@@ -1609,9 +1609,9 @@ export class ConsoleView extends UI.Widget.VBox implements
   }
 }
 
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.Console = globalThis.Console || {};
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.Console.ConsoleView = ConsoleView;
 
 export class ConsoleViewFilter {
diff --git a/front_end/panels/console/ConsoleViewMessage.ts b/front_end/panels/console/ConsoleViewMessage.ts
index 6132e8510b..f93cdd0710 100644
--- a/front_end/panels/console/ConsoleViewMessage.ts
+++ b/front_end/panels/console/ConsoleViewMessage.ts
@@ -314,7 +314,7 @@ export class ConsoleViewMessage implements ConsoleViewportElement {
   protected repeatCountElement: UI.UIUtils.DevToolsSmallBubble|null;
   private requestResolver: Logs.RequestResolver.RequestResolver;
   private issueResolver: IssuesManager.IssueResolver.IssueResolver;
-  #adjacentUserCommandResult: boolean = false;
+  #adjacentUserCommandResult = false;
 
   /** Formatting Error#stack is asynchronous. Allow tests to wait for the result */
   #formatErrorStackPromiseForTest = Promise.resolve();
@@ -673,7 +673,7 @@ export class ConsoleViewMessage implements ConsoleViewportElement {
       this.expandTrace(true);
     }
 
-    // @ts-ignore
+    // @ts-expect-error
     toggleElement._expandStackTraceForTest = this.expandTrace.bind(this, true);
     return toggleElement;
   }
@@ -2263,12 +2263,12 @@ export class ConsoleTableMessageView extends ConsoleViewMessage {
  * The maximum length before strings are considered too long for syntax highlighting.
  * @const
  */
-const MaxLengthToIgnoreHighlighter: number = 10000;
+const MaxLengthToIgnoreHighlighter = 10000;
 
 /**
  * @const
  */
-export const MaxLengthForLinks: number = 40;
+export const MaxLengthForLinks = 40;
 
 let maxTokenizableStringLength = 10000;
 let longStringVisibleLength = 5000;
diff --git a/front_end/panels/coverage/CoverageModel.ts b/front_end/panels/coverage/CoverageModel.ts
index 89783671aa..81395b5b7e 100644
--- a/front_end/panels/coverage/CoverageModel.ts
+++ b/front_end/panels/coverage/CoverageModel.ts
@@ -36,7 +36,7 @@ export interface EventTypes {
   [Events.SourceMapResolved]: void;
 }
 
-const COVERAGE_POLLING_PERIOD_MS: number = 200;
+const COVERAGE_POLLING_PERIOD_MS = 200;
 const RESOLVE_SOURCEMAP_TIMEOUT = 500;
 
 interface BacklogItem<T> {
@@ -320,7 +320,7 @@ export class CoverageModel extends SDK.SDKModel.SDKModel<EventTypes> {
     }
     const {coverage, timestamp} = await this.cpuProfilerModel.takePreciseCoverage();
     this.coverageUpdateTimes.add(timestamp);
-    return this.backlogOrProcessJSCoverage(coverage, timestamp);
+    return await this.backlogOrProcessJSCoverage(coverage, timestamp);
   }
 
   private async backlogOrProcessJSCoverage(
@@ -391,7 +391,7 @@ export class CoverageModel extends SDK.SDKModel.SDKModel<EventTypes> {
     }
     const {coverage, timestamp} = await this.cssModel.takeCoverageDelta();
     this.coverageUpdateTimes.add(timestamp);
-    return this.backlogOrProcessCSSCoverage(coverage, timestamp);
+    return await this.backlogOrProcessCSSCoverage(coverage, timestamp);
   }
 
   private async backlogOrProcessCSSCoverage(freshRawCoverageData: Protocol.CSS.RuleUsage[], freshTimestamp: number):
@@ -859,7 +859,7 @@ export class URLCoverageInfo extends Common.ObjectWrapper.ObjectWrapper<URLCover
     }
 
     // Fall back to the per-script operation.
-    return this.entriesForExportBasedOnContent();
+    return await this.entriesForExportBasedOnContent();
   }
 }
 
@@ -1073,7 +1073,7 @@ export class CoverageInfo {
     }
   }
 
-  rangesForExport(offset: number = 0): Array<{start: number, end: number}> {
+  rangesForExport(offset = 0): Array<{start: number, end: number}> {
     const ranges = [];
     let start = 0;
     for (const segment of this.segments) {
diff --git a/front_end/panels/css_overview/CSSOverviewCompletedView.ts b/front_end/panels/css_overview/CSSOverviewCompletedView.ts
index 3a8d31f0d0..8deaf90b7f 100644
--- a/front_end/panels/css_overview/CSSOverviewCompletedView.ts
+++ b/front_end/panels/css_overview/CSSOverviewCompletedView.ts
@@ -686,7 +686,7 @@ export class CSSOverviewCompletedView extends UI.Widget.VBox {
 
   #groupToFragment(
       items: Map<string, Array<number|UnusedDeclaration|Protocol.CSS.CSSMedia>>, type: string, dataLabel: string,
-      path: string = ''): UI.Fragment.Fragment {
+      path = ''): UI.Fragment.Fragment {
     // Sort by number of items descending.
     const values = Array.from(items.entries()).sort((d1, d2) => {
       const v1Nodes = d1[1];
diff --git a/front_end/panels/developer_resources/DeveloperResourcesView.ts b/front_end/panels/developer_resources/DeveloperResourcesView.ts
index 8fdd6a00b3..edecde3af8 100644
--- a/front_end/panels/developer_resources/DeveloperResourcesView.ts
+++ b/front_end/panels/developer_resources/DeveloperResourcesView.ts
@@ -62,7 +62,7 @@ export class DeveloperResourcesRevealer implements Common.Revealer.Revealer<SDK.
       await UI.ViewManager.ViewManager.instance().showView('developer-resources');
       const developerResourcesView =
           await UI.ViewManager.ViewManager.instance().view('developer-resources').widget() as DeveloperResourcesView;
-      return developerResourcesView.select(resource);
+      return await developerResourcesView.select(resource);
     }
   }
 }
diff --git a/front_end/panels/elements/AccessibilityTreeUtils.ts b/front_end/panels/elements/AccessibilityTreeUtils.ts
index ab8fdc43a4..e1d37d0b18 100644
--- a/front_end/panels/elements/AccessibilityTreeUtils.ts
+++ b/front_end/panels/elements/AccessibilityTreeUtils.ts
@@ -89,7 +89,7 @@ async function getChildren(node: SDK.AccessibilityModel.AccessibilityNode):
     const localRoot = await getRootNode(frameId);
     return [localRoot];
   }
-  return node.accessibilityModel().requestAXChildren(node.id(), node.getFrameId() || undefined);
+  return await node.accessibilityModel().requestAXChildren(node.id(), node.getFrameId() || undefined);
 }
 
 export async function sdkNodeToAXTreeNodes(sdkNode: SDK.AccessibilityModel.AccessibilityNode): Promise<AXTreeNode[]> {
diff --git a/front_end/panels/elements/ClassesPaneWidget.ts b/front_end/panels/elements/ClassesPaneWidget.ts
index 54856e9fc9..d7bf3c6dac 100644
--- a/front_end/panels/elements/ClassesPaneWidget.ts
+++ b/front_end/panels/elements/ClassesPaneWidget.ts
@@ -168,7 +168,7 @@ export class ClassesPaneWidget extends UI.Widget.Widget {
     }
 
     this.classesContainer.removeChildren();
-    // @ts-ignore this.input is a div, not an input element. So this line makes no sense at all
+    // @ts-expect-error this.input is a div, not an input element. So this line makes no sense at all
     this.input.disabled = !node;
 
     if (!node) {
diff --git a/front_end/panels/elements/ComputedStyleModel.ts b/front_end/panels/elements/ComputedStyleModel.ts
index 56a36928a0..8de5e6a3c1 100644
--- a/front_end/panels/elements/ComputedStyleModel.ts
+++ b/front_end/panels/elements/ComputedStyleModel.ts
@@ -178,7 +178,7 @@ export class ComputedStyleModel extends Common.ObjectWrapper.ObjectWrapper<Event
       this.computedStylePromise = cssModel.getComputedStyle(nodeId).then(verifyOutdated.bind(this, elementNode));
     }
 
-    return this.computedStylePromise;
+    return await this.computedStylePromise;
 
     function verifyOutdated(
         this: ComputedStyleModel, elementNode: SDK.DOMModel.DOMNode, style: Map<string, string>|null): ComputedStyle|
diff --git a/front_end/panels/elements/ComputedStyleWidget.test.ts b/front_end/panels/elements/ComputedStyleWidget.test.ts
index 86a27f55fb..ff9b889947 100644
--- a/front_end/panels/elements/ComputedStyleWidget.test.ts
+++ b/front_end/panels/elements/ComputedStyleWidget.test.ts
@@ -14,7 +14,7 @@ async function waitForTraceElement(treeOutline: TreeOutline.TreeOutline.TreeOutl
     return element;
   }
 
-  return new Promise<HTMLElement>(resolve => {
+  return await new Promise<HTMLElement>(resolve => {
     requestAnimationFrame(async () => {
       const result = await waitForTraceElement(treeOutline);
       resolve(result);
diff --git a/front_end/panels/elements/ComputedStyleWidget.ts b/front_end/panels/elements/ComputedStyleWidget.ts
index fad2711151..688d7aa748 100644
--- a/front_end/panels/elements/ComputedStyleWidget.ts
+++ b/front_end/panels/elements/ComputedStyleWidget.ts
@@ -356,7 +356,7 @@ export class ComputedStyleWidget extends UI.ThrottledWidget.ThrottledWidget {
       return null;
     }
 
-    return cssModel.cachedMatchedCascadeForNode(node).then(validateStyles.bind(this));
+    return await cssModel.cachedMatchedCascadeForNode(node).then(validateStyles.bind(this));
 
     function validateStyles(this: ComputedStyleWidget, matchedStyles: SDK.CSSMatchedStyles.CSSMatchedStyles|null):
         SDK.CSSMatchedStyles.CSSMatchedStyles|null {
@@ -466,7 +466,7 @@ export class ComputedStyleWidget extends UI.ThrottledWidget.ThrottledWidget {
       compact: true,
       defaultRenderer,
     };
-    return this.filterGroupLists();
+    return await this.filterGroupLists();
   }
 
   private buildTraceNode(property: SDK.CSSProperty.CSSProperty):
@@ -603,7 +603,7 @@ export class ComputedStyleWidget extends UI.ThrottledWidget.ThrottledWidget {
   async filterComputedStyles(regex: RegExp|null): Promise<void> {
     this.filterRegex = regex;
     if (this.groupComputedStylesSetting.get()) {
-      return this.filterGroupLists();
+      return await this.filterGroupLists();
     }
     return this.filterAlphabeticalList();
   }
diff --git a/front_end/panels/elements/ElementStatePaneWidget.test.ts b/front_end/panels/elements/ElementStatePaneWidget.test.ts
index f7d013202a..d6d8b393c9 100644
--- a/front_end/panels/elements/ElementStatePaneWidget.test.ts
+++ b/front_end/panels/elements/ElementStatePaneWidget.test.ts
@@ -28,8 +28,7 @@ describeWithMockConnection('ElementStatePaneWidget', () => {
   });
 
   const assertExpectedPseudoClasses = async (
-      nodeName: string, expectedPseudoClasses: string[], formAssociated: boolean = false,
-      attribute?: [string, string]) => {
+      nodeName: string, expectedPseudoClasses: string[], formAssociated = false, attribute?: [string, string]) => {
     view = new Elements.ElementStatePaneWidget.ElementStatePaneWidget();
     const tableUpdatedPromise = new Promise<void>(
         resolve => sinon.stub(view, 'updateElementSpecificStatesTableForTest').callsFake(resolve),
diff --git a/front_end/panels/elements/ElementsPanel.ts b/front_end/panels/elements/ElementsPanel.ts
index ff6269a586..307633b566 100644
--- a/front_end/panels/elements/ElementsPanel.ts
+++ b/front_end/panels/elements/ElementsPanel.ts
@@ -1231,9 +1231,9 @@ export class ElementsPanel extends UI.Panel.Panel implements UI.SearchableView.S
   private static firstInspectElementNodeNameForTest = '';
 }
 
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.Elements = globalThis.Elements || {};
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.Elements.ElementsPanel = ElementsPanel;
 
 const enum SplitMode {
diff --git a/front_end/panels/elements/ElementsTreeElement.ts b/front_end/panels/elements/ElementsTreeElement.ts
index 645fcbb1e1..756a273e66 100644
--- a/front_end/panels/elements/ElementsTreeElement.ts
+++ b/front_end/panels/elements/ElementsTreeElement.ts
@@ -578,7 +578,7 @@ export class ElementsTreeElement extends UI.TreeOutline.TreeElement {
 
   override async onpopulate(): Promise<void> {
     if (this.treeOutline) {
-      return this.treeOutline.populateTreeElement(this);
+      return await this.treeOutline.populateTreeElement(this);
     }
   }
 
diff --git a/front_end/panels/elements/ElementsTreeOutline.ts b/front_end/panels/elements/ElementsTreeOutline.ts
index 705005ecd0..feb312b531 100644
--- a/front_end/panels/elements/ElementsTreeOutline.ts
+++ b/front_end/panels/elements/ElementsTreeOutline.ts
@@ -98,7 +98,7 @@ export class ElementsTreeOutline extends
   private visibleWidthInternal?: number;
   private clipboardNodeData?: ClipboardData;
   private isXMLMimeTypeInternal?: boolean|null;
-  suppressRevealAndSelect: boolean = false;
+  suppressRevealAndSelect = false;
   private previousHoveredElement?: UI.TreeOutline.TreeElement;
   private treeElementBeingDragged?: ElementsTreeElement;
   private dragOverTreeElement?: ElementsTreeElement;
@@ -377,7 +377,7 @@ export class ElementsTreeOutline extends
 
   private onCopyOrCut(isCut: boolean, event: Event): void {
     this.setClipboardData(null);
-    // @ts-ignore this bound in the main entry point
+    // @ts-expect-error this bound in the main entry point
     const originalEvent = event['original'];
 
     if (!originalEvent || !originalEvent.target) {
@@ -1771,7 +1771,7 @@ export class Renderer implements UI.UIUtils.Renderer {
       treeOutline.element.classList.add('single-node');
     }
     treeOutline.setVisible(true);
-    // @ts-ignore used in console_test_runner
+    // @ts-expect-error used in console_test_runner
     treeOutline.element.treeElementForTest = firstChild;
     treeOutline.setShowSelectionOnKeyboardFocus(/* show: */ true, /* preventTabOrder: */ true);
     return {node: treeOutline.element, tree: treeOutline};
diff --git a/front_end/panels/elements/LayersWidget.ts b/front_end/panels/elements/LayersWidget.ts
index 1433cef3ea..938e6060c0 100644
--- a/front_end/panels/elements/LayersWidget.ts
+++ b/front_end/panels/elements/LayersWidget.ts
@@ -113,7 +113,7 @@ export class LayersWidget extends UI.Widget.Widget {
       ElementsPanel.instance().showToolbarPane(this, ButtonProvider.instance().item());
     }
     await this.update();
-    return this.layerTreeComponent.expandToAndSelectTreeNodeId('implicit outer layer.' + layerName);
+    return await this.layerTreeComponent.expandToAndSelectTreeNodeId('implicit outer layer.' + layerName);
   }
 
   static instance(opts: {
diff --git a/front_end/panels/elements/StylePropertyTreeElement.test.ts b/front_end/panels/elements/StylePropertyTreeElement.test.ts
index a074ee8b39..30d8ea1fdd 100644
--- a/front_end/panels/elements/StylePropertyTreeElement.test.ts
+++ b/front_end/panels/elements/StylePropertyTreeElement.test.ts
@@ -1114,10 +1114,10 @@ describeWithMockConnection('StylePropertyTreeElement', () => {
       getChildren(): CodeMirror.SyntaxNode[] {
         throw new Error('Method not implemented.');
       }
-      from: number = 0;
-      to: number = 0;
+      from = 0;
+      to = 0;
       type = new CodeMirror.NodeType();
-      name: string = '';
+      name = '';
       tree: CodeMirror.Tree|null = null;
       node: CodeMirror.SyntaxNode = this;
       matchContext(): boolean {
diff --git a/front_end/panels/elements/StylesSidebarPane.ts b/front_end/panels/elements/StylesSidebarPane.ts
index a619992531..5220602e98 100644
--- a/front_end/panels/elements/StylesSidebarPane.ts
+++ b/front_end/panels/elements/StylesSidebarPane.ts
@@ -491,7 +491,7 @@ export class StylesSidebarPane extends Common.ObjectWrapper.eventMixin<EventType
     }
 
     const allDeclarationText: string = lines.join('\n');
-    const ruleText: string = `${selectorText} {\n${allDeclarationText}\n}`;
+    const ruleText = `${selectorText} {\n${allDeclarationText}\n}`;
 
     return {
       allDeclarationText,
@@ -1179,7 +1179,7 @@ export class StylesSidebarPane extends Common.ObjectWrapper.eventMixin<EventType
     let lastParentNode: SDK.DOMModel.DOMNode|null = null;
 
     let lastLayers: SDK.CSSLayer.CSSLayer[]|null = null;
-    let sawLayers: boolean = false;
+    let sawLayers = false;
 
     const addLayerSeparator = (style: SDK.CSSStyleDeclaration.CSSStyleDeclaration): void => {
       const parentRule = style.parentRule;
@@ -2116,7 +2116,7 @@ export class CSSPropertyPrompt extends UI.TextPrompt.TextPrompt {
     const lowerQuery = query.toLowerCase();
     const editingVariable = !this.isEditingName && expression.trim().endsWith('var(');
     if (!query && !force && !editingVariable && (this.isEditingName || expression)) {
-      return Promise.resolve([]);
+      return await Promise.resolve([]);
     }
 
     const prefixResults: CompletionResult[] = [];
@@ -2243,7 +2243,7 @@ export class CSSPropertyPrompt extends UI.TextPrompt.TextPrompt {
         return a.isCSSVariableColor ? -1 : 1;
       });
     }
-    return Promise.resolve(results);
+    return await Promise.resolve(results);
 
     function filterCompletions(
         this: CSSPropertyPrompt, completion: string, variable: boolean, nameValue?: boolean): void {
diff --git a/front_end/panels/elements/TopLayerContainer.test.ts b/front_end/panels/elements/TopLayerContainer.test.ts
index b022a51bf2..93d415e2cc 100644
--- a/front_end/panels/elements/TopLayerContainer.test.ts
+++ b/front_end/panels/elements/TopLayerContainer.test.ts
@@ -31,7 +31,7 @@ describeWithMockConnection('TopLayerContainer', () => {
     const topLayerDOMNode2 = stubTopLayerDOMNode('div', 2, stubDocument);
     const domModel = {
       target: () => createTarget(),
-      getTopLayerElements: async () => Promise.resolve([1 as Protocol.DOM.NodeId, 2 as Protocol.DOM.NodeId]),
+      getTopLayerElements: async () => await Promise.resolve([1 as Protocol.DOM.NodeId, 2 as Protocol.DOM.NodeId]),
       idToDOMNode: new Map([
         [1, topLayerDOMNode1],
         [2, topLayerDOMNode2],
diff --git a/front_end/panels/elements/components/CSSQuery.ts b/front_end/panels/elements/components/CSSQuery.ts
index 9f79c77f4f..c69b6b33e8 100644
--- a/front_end/panels/elements/components/CSSQuery.ts
+++ b/front_end/panels/elements/components/CSSQuery.ts
@@ -30,9 +30,9 @@ export interface CSSQueryData {
 export class CSSQuery extends HTMLElement {
 
   readonly #shadow = this.attachShadow({mode: 'open'});
-  #queryPrefix: string = '';
+  #queryPrefix = '';
   #queryName?: string;
-  #queryText: string = '';
+  #queryText = '';
   #onQueryTextClick?: (event: Event) => void;
   #jslogContext?: string;
 
diff --git a/front_end/panels/elements/components/StylePropertyEditor.ts b/front_end/panels/elements/components/StylePropertyEditor.ts
index b2bddb0769..fa25259ca0 100644
--- a/front_end/panels/elements/components/StylePropertyEditor.ts
+++ b/front_end/panels/elements/components/StylePropertyEditor.ts
@@ -126,7 +126,7 @@ export class StylePropertyEditor extends HTMLElement {
     </div>`;
   }
 
-  #renderButton(propertyValue: string, propertyName: string, selected: boolean = false): Lit.TemplateResult {
+  #renderButton(propertyValue: string, propertyName: string, selected = false): Lit.TemplateResult {
     const query = `${propertyName}: ${propertyValue}`;
     const iconInfo = this.findIcon(query, this.#computedProperties);
     if (!iconInfo) {
diff --git a/front_end/panels/emulation/AdvancedApp.ts b/front_end/panels/emulation/AdvancedApp.ts
index d943276b9e..532d6ff64d 100644
--- a/front_end/panels/emulation/AdvancedApp.ts
+++ b/front_end/panels/emulation/AdvancedApp.ts
@@ -183,9 +183,9 @@ export class AdvancedApp implements Common.App.App {
 }
 
 // Export required for usage in toolbox.ts
-// @ts-ignore Exported for Tests.js
+// @ts-expect-error Exported for Tests.js
 globalThis.Emulation = globalThis.Emulation || {};
-// @ts-ignore Exported for Tests.js
+// @ts-expect-error Exported for Tests.js
 globalThis.Emulation.AdvancedApp = AdvancedApp;
 
 let advancedAppProviderInstance: AdvancedAppProvider;
diff --git a/front_end/panels/event_listeners/EventListenersUtils.ts b/front_end/panels/event_listeners/EventListenersUtils.ts
index 95214e9177..b08d03da2a 100644
--- a/front_end/panels/event_listeners/EventListenersUtils.ts
+++ b/front_end/panels/event_listeners/EventListenersUtils.ts
@@ -13,7 +13,7 @@ export async function frameworkEventListeners(object: SDK.RemoteObject.RemoteObj
   }
 
   const listenersResult = {internalHandlers: null, eventListeners: []} as FrameworkEventListenersObject;
-  return object.callFunction(frameworkEventListenersImpl, undefined)
+  return await object.callFunction(frameworkEventListenersImpl, undefined)
       .then(assertCallFunctionResult)
       .then(getOwnProperties)
       .then(createEventListeners)
@@ -218,9 +218,9 @@ export async function frameworkEventListeners(object: SDK.RemoteObject.RemoteObj
     let internalHandlers: Array<() => void> = [];
     let fetchers = [jQueryFetcher];
     try {
-      // @ts-ignore Here because of layout tests.
+      // @ts-expect-error Here because of layout tests.
       if (self.devtoolsFrameworkEventListeners && isArrayLike(self.devtoolsFrameworkEventListeners)) {
-        // @ts-ignore Here because of layout tests.
+        // @ts-expect-error Here because of layout tests.
         fetchers = fetchers.concat(self.devtoolsFrameworkEventListeners);
       }
     } catch (e) {
@@ -298,8 +298,8 @@ export async function frameworkEventListeners(object: SDK.RemoteObject.RemoteObj
       return false;
     }
 
-    function checkEventListener(eventListener: PossibleEventListenerObjectInInspectedPage|
-                                null): EventListenerObjectInInspectedPage|null {
+    function checkEventListener(eventListener: PossibleEventListenerObjectInInspectedPage|null):
+        EventListenerObjectInInspectedPage|null {
       try {
         let errorString = '';
         if (!eventListener) {
@@ -445,8 +445,7 @@ export async function frameworkEventListeners(object: SDK.RemoteObject.RemoteObj
         return;
       }
       const jQueryFunction = jQuery as (arg0: Node) => {
-        off:
-          Function,
+        off: Function,
       };
       jQueryFunction(node).off(type, selector, handler);
     }
diff --git a/front_end/panels/event_listeners/EventListenersView.ts b/front_end/panels/event_listeners/EventListenersView.ts
index 280593dfac..f3d162fd51 100644
--- a/front_end/panels/event_listeners/EventListenersView.ts
+++ b/front_end/panels/event_listeners/EventListenersView.ts
@@ -126,7 +126,7 @@ export class EventListenersView extends UI.Widget.VBox {
       if (!frameworkEventListenersObject.internalHandlers) {
         return;
       }
-      return frameworkEventListenersObject.internalHandlers.object()
+      return await frameworkEventListenersObject.internalHandlers.object()
           .callFunctionJSON(isInternalEventListener as (this: Object) => boolean[], eventListeners.map(handlerArgument))
           .then(setIsInternal);
 
diff --git a/front_end/panels/issues/IssueView.ts b/front_end/panels/issues/IssueView.ts
index 58e5ef17a2..474b3896b5 100644
--- a/front_end/panels/issues/IssueView.ts
+++ b/front_end/panels/issues/IssueView.ts
@@ -224,7 +224,7 @@ export class IssueView extends UI.TreeOutline.TreeElement {
   #throttle: Common.Throttler.Throttler;
   #needsUpdateOnExpand = true;
   #hiddenIssuesMenu?: Components.HideIssuesMenu.HideIssuesMenu;
-  #contentCreated: boolean = false;
+  #contentCreated = false;
 
   constructor(issue: AggregatedIssue, description: IssuesManager.MarkdownIssueDescription.IssueDescription) {
     super();
diff --git a/front_end/panels/layer_viewer/Layers3DView.ts b/front_end/panels/layer_viewer/Layers3DView.ts
index bdd8752e01..97153e08d5 100644
--- a/front_end/panels/layer_viewer/Layers3DView.ts
+++ b/front_end/panels/layer_viewer/Layers3DView.ts
@@ -798,7 +798,7 @@ export class Layers3DView extends Common.ObjectWrapper.eventMixin<EventTypes, ty
     if (!this.layerTree) {
       return null;
     }
-    let closestIntersectionPoint: number = Infinity;
+    let closestIntersectionPoint = Infinity;
     let closestObject: Selection|null = null;
     const projectionMatrix =
         new WebKitCSSMatrix().scale(1, -1, -1).translate(-1, -1, 0).multiply(this.projectionMatrix);
diff --git a/front_end/panels/lighthouse/LighthouseProtocolService.ts b/front_end/panels/lighthouse/LighthouseProtocolService.ts
index 61f573bfb3..9c38b78fac 100644
--- a/front_end/panels/lighthouse/LighthouseProtocolService.ts
+++ b/front_end/panels/lighthouse/LighthouseProtocolService.ts
@@ -152,7 +152,7 @@ export class ProtocolService {
       mode = 'endTimespan';
     }
 
-    return this.sendWithResponse(mode, {
+    return await this.sendWithResponse(mode, {
       url: inspectedURL,
       categoryIDs,
       flags,
@@ -283,6 +283,6 @@ export class ProtocolService {
     });
     worker.postMessage({id: messageId, action, args: {...args, id: messageId}});
 
-    return messageResult;
+    return await messageResult;
   }
 }
diff --git a/front_end/panels/lighthouse/LighthouseReportRenderer.ts b/front_end/panels/lighthouse/LighthouseReportRenderer.ts
index 8312497267..3a731df652 100644
--- a/front_end/panels/lighthouse/LighthouseReportRenderer.ts
+++ b/front_end/panels/lighthouse/LighthouseReportRenderer.ts
@@ -88,9 +88,9 @@ export class LighthouseReportRenderer {
         ThemeSupport.ThemeChangeEvent.eventName, updateDarkModeIfNecessary);
     updateDarkModeIfNecessary();
 
-    // @ts-ignore Expose LHR on DOM for e2e tests
+    // @ts-expect-error Expose LHR on DOM for e2e tests
     reportEl._lighthouseResultForTesting = lhr;
-    // @ts-ignore Expose Artifacts on DOM for e2e tests
+    // @ts-expect-error Expose Artifacts on DOM for e2e tests
     reportEl._lighthouseArtifactsForTesting = artifacts;
 
     // This should block the report rendering as we need visual logging ready
diff --git a/front_end/panels/lighthouse/LighthouseStatusView.ts b/front_end/panels/lighthouse/LighthouseStatusView.ts
index 76c4cbac7f..6f59897635 100644
--- a/front_end/panels/lighthouse/LighthouseStatusView.ts
+++ b/front_end/panels/lighthouse/LighthouseStatusView.ts
@@ -244,7 +244,6 @@ export class StatusView {
     const statusHeader =
         pageHost ? i18nString(UIStrings.auditingS, {PH1: pageHost}) : i18nString(UIStrings.auditingYourWebPage);
     this.renderStatusHeader(statusHeader);
-    // @ts-ignore TS expects Document, but gets Element (show takes Element|Document)
     this.dialog.show(dialogRenderElement);
   }
 
@@ -260,7 +259,7 @@ export class StatusView {
     }
   }
 
-  setInspectedURL(url: string = ''): void {
+  setInspectedURL(url = ''): void {
     this.inspectedURL = url;
   }
 
@@ -288,7 +287,6 @@ export class StatusView {
 
       if (this.progressBar) {
         this.progressBar.classList.add(nextPhase.progressBarClass);
-        // @ts-ignore indexOf null is valid.
         const nextPhaseIndex = StatusPhases.indexOf(nextPhase);
         UI.ARIAUtils.setProgressBarValue(this.progressBar, nextPhaseIndex, text);
       }
@@ -398,7 +396,7 @@ export class StatusView {
 
   private renderBugReportBody(err: Error, auditURL: string): void {
     const chromeVersion = navigator.userAgent.match(/Chrome\/(\S+)/) || ['', 'Unknown'];
-    // @ts-ignore Lighthouse sets `friendlyMessage` on certain
+    // @ts-expect-error Lighthouse sets `friendlyMessage` on certain
     // important errors such as PROTOCOL_TIMEOUT.
     const errorMessage = err.friendlyMessage || err.message;
     const issueBody = `
diff --git a/front_end/panels/media/EventTimelineView.ts b/front_end/panels/media/EventTimelineView.ts
index bf2f75302e..1677427cc6 100644
--- a/front_end/panels/media/EventTimelineView.ts
+++ b/front_end/panels/media/EventTimelineView.ts
@@ -162,9 +162,9 @@ export class PlayerEventsTimeline extends TickingFlameChart {
         // We only want the buffering for audio and video to be displayed.
         // One event may have changes for a single type, or for both audio/video
         // simultaneously.
-        // @ts-ignore
+        // @ts-expect-error
         audioState = event.value['audio_buffering_state'];
-        // @ts-ignore
+        // @ts-expect-error
         videoState = event.value['video_buffering_state'];
 
         if (audioState) {
diff --git a/front_end/panels/media/MediaModel.ts b/front_end/panels/media/MediaModel.ts
index 7f13a243d8..821b2a7e14 100644
--- a/front_end/panels/media/MediaModel.ts
+++ b/front_end/panels/media/MediaModel.ts
@@ -43,7 +43,7 @@ export class MediaModel extends SDK.SDKModel.SDKModel<EventTypes> implements Pro
 
   override async resumeModel(): Promise<void> {
     if (!this.enabled) {
-      return Promise.resolve();
+      return await Promise.resolve();
     }
     await this.agent.invoke_enable();
   }
diff --git a/front_end/panels/media/TickingFlameChart.ts b/front_end/panels/media/TickingFlameChart.ts
index d72d2c29cb..1c376fff6e 100644
--- a/front_end/panels/media/TickingFlameChart.ts
+++ b/front_end/panels/media/TickingFlameChart.ts
@@ -318,7 +318,7 @@ export class TickingFlameChart extends UI.Widget.VBox {
     this.ticking = true;
   }
 
-  private stop(permanently: boolean = false): void {
+  private stop(permanently = false): void {
     window.clearInterval(this.intervalTimer);
     this.intervalTimer = 0;
     if (permanently) {
diff --git a/front_end/panels/mobile_throttling/ThrottlingPresets.ts b/front_end/panels/mobile_throttling/ThrottlingPresets.ts
index bed99c92c8..6b1e3c0731 100644
--- a/front_end/panels/mobile_throttling/ThrottlingPresets.ts
+++ b/front_end/panels/mobile_throttling/ThrottlingPresets.ts
@@ -188,9 +188,9 @@ export class ThrottlingPresets {
   ];
 }
 
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.MobileThrottling = globalThis.MobileThrottling || {};
-// @ts-ignore exported for Tests.js
+// @ts-expect-error exported for Tests.js
 globalThis.MobileThrottling.networkPresets = ThrottlingPresets.networkPresets;
 
 export interface Conditions {
diff --git a/front_end/panels/network/RequestPayloadView.ts b/front_end/panels/network/RequestPayloadView.ts
index 458d723f97..8aab123074 100644
--- a/front_end/panels/network/RequestPayloadView.ts
+++ b/front_end/panels/network/RequestPayloadView.ts
@@ -461,7 +461,7 @@ export class RequestPayloadView extends UI.Widget.VBox {
     // `editable` is not a valid property for `ObjectUI.ObjectPropertiesSection.RootElement`. Only for
     // `ObjectUI.ObjectPropertiesSection.ObjectPropertiesSection`. We do not know if this assignment is
     // safe to delete.
-    // @ts-ignore
+    // @ts-expect-error
     section.editable = false;
     rootListItem.childrenListElement.classList.add('source-code', 'object-properties-section');
 
diff --git a/front_end/panels/network/components/EditableSpan.ts b/front_end/panels/network/components/EditableSpan.ts
index 6a136f8d38..acab82c791 100644
--- a/front_end/panels/network/components/EditableSpan.ts
+++ b/front_end/panels/network/components/EditableSpan.ts
@@ -19,7 +19,7 @@ export interface EditableSpanData {
 export class EditableSpan extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   readonly #boundRender = this.#render.bind(this);
-  #value: string = '';
+  #value = '';
 
   connectedCallback(): void {
     this.#shadow.adoptedStyleSheets = [editableSpanStyles];
diff --git a/front_end/panels/network/components/RequestHeadersView.ts b/front_end/panels/network/components/RequestHeadersView.ts
index f5ebe7b362..aedc499ac8 100644
--- a/front_end/panels/network/components/RequestHeadersView.ts
+++ b/front_end/panels/network/components/RequestHeadersView.ts
@@ -199,7 +199,7 @@ export class RequestHeadersView extends LegacyWrapper.LegacyWrapper.WrappableCom
       return;
     }
 
-    return RenderCoordinator.write(() => {
+    return await RenderCoordinator.write(() => {
       // Disabled until https://crbug.com/1079231 is fixed.
       // clang-format off
       render(html`
diff --git a/front_end/panels/network/components/ResponseHeaderSection.test.ts b/front_end/panels/network/components/ResponseHeaderSection.test.ts
index 70e9b91b36..8e20133e75 100644
--- a/front_end/panels/network/components/ResponseHeaderSection.test.ts
+++ b/front_end/panels/network/components/ResponseHeaderSection.test.ts
@@ -96,7 +96,7 @@ async function setupHeaderEditing(
     setAssociatedData: () => {},
   } as unknown as SDK.NetworkRequest.NetworkRequest;
 
-  return setupHeaderEditingWithRequest(headerOverridesFileContent, request);
+  return await setupHeaderEditingWithRequest(headerOverridesFileContent, request);
 }
 
 async function setupHeaderEditingWithRequest(
@@ -125,8 +125,8 @@ async function setupHeaderEditingWithRequest(
 
 function checkHeaderSectionRow(
     row: NetworkComponents.HeaderSectionRow.HeaderSectionRow, headerName: string, headerValue: string,
-    isOverride: boolean, isNameEditable: boolean, isValueEditable: boolean, isHighlighted: boolean = false,
-    isDeleted: boolean = false): void {
+    isOverride: boolean, isNameEditable: boolean, isValueEditable: boolean, isHighlighted = false,
+    isDeleted = false): void {
   assert.isNotNull(row.shadowRoot);
   const rowElement = row.shadowRoot.querySelector('.row');
   assert.strictEqual(rowElement?.classList.contains('header-overridden'), isOverride);
diff --git a/front_end/panels/performance_monitor/PerformanceMonitor.ts b/front_end/panels/performance_monitor/PerformanceMonitor.ts
index 94d6a3bced..8ab2571976 100644
--- a/front_end/panels/performance_monitor/PerformanceMonitor.ts
+++ b/front_end/panels/performance_monitor/PerformanceMonitor.ts
@@ -75,7 +75,7 @@ export class PerformanceMonitorImpl extends UI.Widget.HBox implements
   private startTimestamp?: number;
   private pollTimer?: number;
 
-  constructor(pollIntervalMs: number = 500) {
+  constructor(pollIntervalMs = 500) {
     super(true);
     this.registerRequiredCSS(performanceMonitorStyles);
 
@@ -289,7 +289,7 @@ export class PerformanceMonitorImpl extends UI.Widget.HBox implements
     }
     const width = this.width;
     const startTime = performance.now() - this.pollIntervalMs - width / this.pixelsPerMs;
-    let max: number = -Infinity;
+    let max = -Infinity;
     for (const metricInfo of chartInfo.metrics) {
       for (let i = this.metricsBuffer.length - 1; i >= 0; --i) {
         const metrics = this.metricsBuffer[i];
diff --git a/front_end/panels/profiler/HeapDetachedElementsDataGrid.ts b/front_end/panels/profiler/HeapDetachedElementsDataGrid.ts
index 5be1c0ef51..aed4755012 100644
--- a/front_end/panels/profiler/HeapDetachedElementsDataGrid.ts
+++ b/front_end/panels/profiler/HeapDetachedElementsDataGrid.ts
@@ -86,7 +86,7 @@ export class HeapDetachedElementsDataGridNode extends DataGrid.DataGrid.DataGrid
   }
 
   #getNodeSize(detachedElementInfo: Protocol.DOM.DetachedElementInfo): number {
-    let count: number = 1;
+    let count = 1;
     const queue: Protocol.DOM.Node[] = [];
     let node: Protocol.DOM.Node|undefined;
     queue.push(detachedElementInfo.treeNode);
@@ -117,7 +117,7 @@ export class HeapDetachedElementsDataGridNode extends DataGrid.DataGrid.DataGrid
       treeOutline.element.classList.add('single-node');
     }
     treeOutline.setVisible(true);
-    // @ts-ignore used in console_test_runner
+    // @ts-expect-error used in console_test_runner
     treeOutline.element.treeElementForTest = firstChild;
     treeOutline.setShowSelectionOnKeyboardFocus(/* show: */ true, /* preventTabOrder: */ true);
 
diff --git a/front_end/panels/profiler/HeapSnapshotDataGrids.ts b/front_end/panels/profiler/HeapSnapshotDataGrids.ts
index 6e522d29bb..7b8bc930e9 100644
--- a/front_end/panels/profiler/HeapSnapshotDataGrids.ts
+++ b/front_end/panels/profiler/HeapSnapshotDataGrids.ts
@@ -155,9 +155,9 @@ const adjacencyMap = new WeakMap<DataGrid.DataGrid.DataGridNode<HeapSnapshotGrid
 
 class HeapSnapshotSortableDataGridBase extends DataGrid.DataGrid.DataGridImpl<HeapSnapshotGridNode> {}
 
-export class HeapSnapshotSortableDataGrid extends
-    Common.ObjectWrapper.eventMixin<EventTypes, typeof HeapSnapshotSortableDataGridBase>(
-        HeapSnapshotSortableDataGridBase) {
+export class HeapSnapshotSortableDataGrid extends Common.ObjectWrapper
+                                                      .eventMixin<EventTypes, typeof HeapSnapshotSortableDataGridBase>(
+                                                          HeapSnapshotSortableDataGridBase) {
   snapshot: HeapSnapshotProxy|null;
   override selectedNode: HeapSnapshotGridNode|null;
   readonly heapProfilerModelInternal: SDK.HeapProfilerModel.HeapProfilerModel|null;
@@ -322,9 +322,9 @@ export class HeapSnapshotSortableDataGrid extends
     function sortByTwoFields(
         nodeA: DataGrid.DataGrid.DataGridNode<HeapSnapshotGridNode>,
         nodeB: DataGrid.DataGrid.DataGridNode<HeapSnapshotGridNode>): number {
-      // @ts-ignore
+      // @ts-expect-error
       let field1 = nodeA[sortFields.fieldName1];
-      // @ts-ignore
+      // @ts-expect-error
       let field2 = nodeB[sortFields.fieldName1];
       let result: number|(0 | 1 | -1) = field1 < field2 ? -1 : (field1 > field2 ? 1 : 0);
       if (!sortFields.ascending1) {
@@ -333,9 +333,9 @@ export class HeapSnapshotSortableDataGrid extends
       if (result !== 0) {
         return result;
       }
-      // @ts-ignore
+      // @ts-expect-error
       field1 = nodeA[sortFields.fieldName2];
-      // @ts-ignore
+      // @ts-expect-error
       field2 = nodeB[sortFields.fieldName2];
       result = field1 < field2 ? -1 : (field1 > field2 ? 1 : 0);
       if (!sortFields.ascending2) {
@@ -835,7 +835,7 @@ export class HeapSnapshotConstructorsDataGrid extends HeapSnapshotViewportDataGr
     }
 
     const nodes = await parent.populateNodeBySnapshotObjectId(parseInt(id, 10));
-    return nodes.length ? this.revealTreeNode(nodes) : null;
+    return nodes.length ? await this.revealTreeNode(nodes) : null;
   }
 
   clear(): void {
@@ -1071,11 +1071,11 @@ export class AllocationDataGrid extends HeapSnapshotViewportDataGrid {
     const fieldName = this.sortColumnId();
     const compareResult = (this.sortOrder() === DataGrid.DataGrid.Order.Ascending) ? +1 : -1;
     function compare(a: Object, b: Object): number {
-      // @ts-ignore
+      // @ts-expect-error
       if (a[fieldName] > b[fieldName]) {
         return compareResult;
       }
-      // @ts-ignore
+      // @ts-expect-error
       if (a[fieldName] < b[fieldName]) {
         return -compareResult;
       }
diff --git a/front_end/panels/profiler/HeapSnapshotView.ts b/front_end/panels/profiler/HeapSnapshotView.ts
index fad74ce841..12feb9f163 100644
--- a/front_end/panels/profiler/HeapSnapshotView.ts
+++ b/front_end/panels/profiler/HeapSnapshotView.ts
@@ -326,7 +326,7 @@ export class HeapSnapshotView extends UI.View.SimpleView implements DataDisplayD
   readonly searchThrottler: Common.Throttler.Throttler;
   baseProfile!: HeapProfileHeader|null;
   trackingOverviewGrid?: HeapTimelineOverview;
-  currentSearchResultIndex: number = -1;
+  currentSearchResultIndex = -1;
   currentQuery?: HeapSnapshotModel.HeapSnapshotModel.SearchConfig;
   constructor(dataDisplayDelegate: DataDisplayDelegate, profile: HeapProfileHeader) {
     super(i18nString(UIStrings.heapSnapshot));
@@ -1681,7 +1681,7 @@ export class HeapProfileHeader extends ProfileHeader {
     if (!this.snapshotProxy) {
       return null;
     }
-    return this.snapshotProxy.getLocation(nodeIndex);
+    return await this.snapshotProxy.getLocation(nodeIndex);
   }
 
   override createSidebarTreeElement(dataDisplayDelegate: DataDisplayDelegate): ProfileSidebarTreeElement {
diff --git a/front_end/panels/profiler/ProfileDataGrid.ts b/front_end/panels/profiler/ProfileDataGrid.ts
index 7ec8d6ea0e..a754f89484 100644
--- a/front_end/panels/profiler/ProfileDataGrid.ts
+++ b/front_end/panels/profiler/ProfileDataGrid.ts
@@ -348,7 +348,7 @@ export class ProfileDataGridTree implements UI.SearchableView.Searchable {
   }>;
   savedTotal?: number;
   savedChildren?: ProfileDataGridNode[]|null;
-  searchResultIndex: number = -1;
+  searchResultIndex = -1;
 
   constructor(formatter: Formatter, searchableView: UI.SearchableView.SearchableView, total: number) {
     this.tree = this;
diff --git a/front_end/panels/profiler/ProfileFlameChartDataProvider.ts b/front_end/panels/profiler/ProfileFlameChartDataProvider.ts
index c7c1348970..96e8a658df 100644
--- a/front_end/panels/profiler/ProfileFlameChartDataProvider.ts
+++ b/front_end/panels/profiler/ProfileFlameChartDataProvider.ts
@@ -151,7 +151,7 @@ export class ProfileFlameChart extends
   entrySelected: boolean;
   readonly dataProvider: ProfileFlameChartDataProvider;
   searchResults: number[];
-  searchResultIndex: number = -1;
+  searchResultIndex = -1;
 
   constructor(searchableView: UI.SearchableView.SearchableView, dataProvider: ProfileFlameChartDataProvider) {
     super();
diff --git a/front_end/panels/profiler/ProfileView.ts b/front_end/panels/profiler/ProfileView.ts
index 239cefa0ca..e1a363a80d 100644
--- a/front_end/panels/profiler/ProfileView.ts
+++ b/front_end/panels/profiler/ProfileView.ts
@@ -342,7 +342,7 @@ export class ProfileView extends UI.View.SimpleView implements UI.SearchableView
 
     if (selectedProfileNode) {
       // TODO(crbug.com/1011811): Cleanup the added `selected` property to this SDK class.
-      // @ts-ignore
+      // @ts-expect-error
       selectedProfileNode.selected = true;
     }
   }
@@ -627,7 +627,7 @@ export class WritableProfileHeader extends ProfileHeader implements Common.Strin
     }
 
     this.updateStatus(i18nString(UIStrings.parsing), true);
-    let error: null = null;
+    let error = null;
     try {
       this.profile = (JSON.parse(this.jsonifiedProfile) as Protocol.Profiler.Profile);
       this.setProfile((this.profile));
diff --git a/front_end/panels/protocol_monitor/JSONEditor.ts b/front_end/panels/protocol_monitor/JSONEditor.ts
index 042a8d10e5..2682b2645e 100644
--- a/front_end/panels/protocol_monitor/JSONEditor.ts
+++ b/front_end/panels/protocol_monitor/JSONEditor.ts
@@ -146,7 +146,7 @@ export class JSONEditor extends Common.ObjectWrapper.eventMixin<EventTypes, type
   #enumsByName: Map<string, Record<string, string>>;
   #parameters: Parameter[] = [];
   #targets: SDK.Target.Target[] = [];
-  #command: string = '';
+  #command = '';
   #targetId?: string;
   #hintPopoverHelper?: UI.PopoverHelper.PopoverHelper;
 
diff --git a/front_end/panels/protocol_monitor/ProtocolMonitor.ts b/front_end/panels/protocol_monitor/ProtocolMonitor.ts
index 6a3e6bcaeb..5be417430b 100644
--- a/front_end/panels/protocol_monitor/ProtocolMonitor.ts
+++ b/front_end/panels/protocol_monitor/ProtocolMonitor.ts
@@ -498,7 +498,7 @@ export class ProtocolMonitorDataGrid extends Common.ObjectWrapper.eventMixin<Eve
     const sessionId = selectedTarget ? selectedTarget.sessionId : '';
     // TS thinks that properties are read-only because
     // in TS test is defined as a namespace.
-    // @ts-ignore
+    // @ts-expect-error
     test.sendRawMessage(command, parameters, () => {}, sessionId);
   }
 
@@ -515,16 +515,11 @@ export class ProtocolMonitorDataGrid extends Common.ObjectWrapper.eventMixin<Eve
   private setRecording(recording: boolean): void {
     const test = ProtocolClient.InspectorBackend.test;
     if (recording) {
-      // TODO: TS thinks that properties are read-only because
-      // in TS test is defined as a namespace.
-      // @ts-ignore
       test.onMessageSent = this.messageSent.bind(this);
-      // @ts-ignore
+      // @ts-expect-error
       test.onMessageReceived = this.messageReceived.bind(this);
     } else {
-      // @ts-ignore
       test.onMessageSent = null;
-      // @ts-ignore
       test.onMessageReceived = null;
     }
   }
diff --git a/front_end/panels/recorder/RecorderController.ts b/front_end/panels/recorder/RecorderController.ts
index a978540494..bcce705aa1 100644
--- a/front_end/panels/recorder/RecorderController.ts
+++ b/front_end/panels/recorder/RecorderController.ts
@@ -462,7 +462,7 @@ export class RecorderController extends LitElement {
       this.viewDescriptor = undefined;
     }
     if (event.data.extension) {
-      return this.#onPlayViaExtension(event.data.extension);
+      return await this.#onPlayViaExtension(event.data.extension);
     }
     Host.userMetrics.recordingReplayStarted(
         event.data.targetPanel !== Components.RecordingView.TargetPanel.DEFAULT ?
diff --git a/front_end/panels/recorder/components/CreateRecordingView.ts b/front_end/panels/recorder/components/CreateRecordingView.ts
index d81d686b98..642b43e995 100644
--- a/front_end/panels/recorder/components/CreateRecordingView.ts
+++ b/front_end/panels/recorder/components/CreateRecordingView.ts
@@ -146,7 +146,7 @@ export interface CreateRecordingViewData {
 
 export class CreateRecordingView extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
-  #defaultRecordingName: string = '';
+  #defaultRecordingName = '';
   #error?: Error;
   #recorderSettings?: Models.RecorderSettings.RecorderSettings;
 
diff --git a/front_end/panels/recorder/components/RecordingView.ts b/front_end/panels/recorder/components/RecordingView.ts
index e45cf47198..3f3e435bf2 100644
--- a/front_end/panels/recorder/components/RecordingView.ts
+++ b/front_end/panels/recorder/components/RecordingView.ts
@@ -314,8 +314,8 @@ export class RecordingView extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   #replayState: ReplayState = {isPlaying: false, isPausedOnBreakpoint: false};
   #userFlow: Models.Schema.UserFlow|null = null;
-  #isRecording: boolean = false;
-  #recordingTogglingInProgress: boolean = false;
+  #isRecording = false;
+  #recordingTogglingInProgress = false;
   #isTitleInvalid = false;
   #currentStep?: Models.Schema.Step;
   #steps: Models.Schema.Step[] = [];
@@ -333,8 +333,8 @@ export class RecordingView extends HTMLElement {
   #extensionConverters: Converters.Converter.Converter[] = [];
   #replayExtensions?: Extensions.ExtensionManager.Extension[];
   #showCodeView = false;
-  #code: string = '';
-  #converterId: string = '';
+  #code = '';
+  #converterId = '';
   #editorState?: CodeMirror.EditorState;
   #sourceMap: PuppeteerReplay.SourceMap|undefined;
   #extensionDescriptor?: PublicExtensions.RecorderPluginManager.ViewDescriptor;
diff --git a/front_end/panels/recorder/components/StepEditor.ts b/front_end/panels/recorder/components/StepEditor.ts
index 830aaccb30..1bf13cde9d 100644
--- a/front_end/panels/recorder/components/StepEditor.ts
+++ b/front_end/panels/recorder/components/StepEditor.ts
@@ -368,7 +368,7 @@ export class EditorState {
       attribute: Attribute): Promise<DeepImmutable<typeof defaultValuesByAttribute[Attribute]>>;
   static async defaultByAttribute(_state: DeepImmutable<EditorState>, attribute: keyof typeof defaultValuesByAttribute):
       Promise<unknown> {
-    return this.#puppeteer.run(puppeteer => {
+    return await this.#puppeteer.run(puppeteer => {
       switch (attribute) {
         case 'assertedEvents': {
           return immutableDeepAssign(defaultValuesByAttribute.assertedEvents, new ArrayAssignments({
@@ -401,7 +401,7 @@ export class EditorState {
     const state = structuredClone(step) as EditorState;
     for (const key of ['parameters', 'properties'] as Array<'properties'>) {
       if (key in step && step[key] !== undefined) {
-        // @ts-ignore Potential infinite type instantiation.
+        // @ts-expect-error Potential infinite type instantiation.
         state[key] = JSON.stringify(step[key]);
       }
     }
diff --git a/front_end/panels/recorder/models/RecordingPlayer.ts b/front_end/panels/recorder/models/RecordingPlayer.ts
index eb8922df1a..a70706b9b2 100644
--- a/front_end/panels/recorder/models/RecordingPlayer.ts
+++ b/front_end/panels/recorder/models/RecordingPlayer.ts
@@ -47,7 +47,7 @@ export class RecordingPlayer extends Common.ObjectWrapper.ObjectWrapper<EventTyp
   speed: PlayRecordingSpeed;
   timeout: number;
   breakpointIndexes: Set<number>;
-  steppingOver: boolean = false;
+  steppingOver = false;
   aborted = false;
   abortPromise: Promise<void>;
   #abortResolveFn?: Function;
diff --git a/front_end/panels/recorder/models/RecordingStorage.ts b/front_end/panels/recorder/models/RecordingStorage.ts
index eb2c66127d..1d5340bfc4 100644
--- a/front_end/panels/recorder/models/RecordingStorage.ts
+++ b/front_end/panels/recorder/models/RecordingStorage.ts
@@ -14,7 +14,6 @@ interface IdGenerator {
 
 class UUIDGenerator implements IdGenerator {
   next(): string {
-    // @ts-ignore
     return crypto.randomUUID();
   }
 }
diff --git a/front_end/panels/recorder/util/util.ts b/front_end/panels/recorder/util/util.ts
index c1950feee7..0ab277a028 100644
--- a/front_end/panels/recorder/util/util.ts
+++ b/front_end/panels/recorder/util/util.ts
@@ -18,7 +18,7 @@ class InjectedScript {
                                   ))
                                  .text();
     }
-    return this.#injectedScript;
+    return await this.#injectedScript;
   }
 }
 
diff --git a/front_end/panels/screencast/ScreencastView.ts b/front_end/panels/screencast/ScreencastView.ts
index 49614a7e9b..9ba8b74249 100644
--- a/front_end/panels/screencast/ScreencastView.ts
+++ b/front_end/panels/screencast/ScreencastView.ts
@@ -132,7 +132,7 @@ export class ScreencastView extends UI.Widget.VBox implements SDK.OverlayModel.H
   private mouseInputToggleIcon?: IconButton.Icon.Icon;
   private historyIndex?: number;
   private historyEntries?: Protocol.Page.NavigationEntry[];
-  private isCasting: boolean = false;
+  private isCasting = false;
   private screencastOperationId?: number;
   constructor(screenCaptureModel: SDK.ScreenCaptureModel.ScreenCaptureModel) {
     super();
diff --git a/front_end/panels/security/CookieReportView.test.ts b/front_end/panels/security/CookieReportView.test.ts
index 4c1165a16c..b2868ab660 100644
--- a/front_end/panels/security/CookieReportView.test.ts
+++ b/front_end/panels/security/CookieReportView.test.ts
@@ -60,7 +60,7 @@ describeWithMockConnection('CookieReportView', () => {
   });
 
   it('should have row when there was a preexisting cookie issue', async () => {
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue());
 
     const view = new Security.CookieReportView.CookieReportView(undefined, mockView);
@@ -75,7 +75,7 @@ describeWithMockConnection('CookieReportView', () => {
 
     assert.lengthOf(mockView.lastCall.firstArg.cookieRows, 0);
 
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue());
     await view.updateComplete;
 
@@ -85,7 +85,7 @@ describeWithMockConnection('CookieReportView', () => {
   it('should ignore non-third-party-cookie related exclusionReason', async () => {
     const view = new Security.CookieReportView.CookieReportView(undefined, mockView);
 
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(
         getTestCookieIssue(undefined, Protocol.Audits.CookieExclusionReason.ExcludeSameSiteNoneInsecure));
     await view.updateComplete;
@@ -93,7 +93,7 @@ describeWithMockConnection('CookieReportView', () => {
     assert.lengthOf(mockView.lastCall.firstArg.cookieRows, 0);
 
     // Make sure ExcludeThirdPartyPhaseout (default) is added.
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue());
     await view.updateComplete;
 
@@ -104,7 +104,7 @@ describeWithMockConnection('CookieReportView', () => {
   it('should ignore non-third-party-cookie related warningReason', async () => {
     const view = new Security.CookieReportView.CookieReportView(undefined, mockView);
 
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(
         getTestCookieIssue(undefined, undefined, Protocol.Audits.CookieWarningReason.WarnSameSiteLaxCrossDowngradeLax));
     await view.updateComplete;
@@ -112,13 +112,13 @@ describeWithMockConnection('CookieReportView', () => {
     assert.lengthOf(mockView.lastCall.firstArg.cookieRows, 0);
 
     // Make sure warning 3pc warning reasons are added
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(
         undefined, undefined, Protocol.Audits.CookieWarningReason.WarnDeprecationTrialMetadata, 'metadata'));
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(
         undefined, undefined, Protocol.Audits.CookieWarningReason.WarnThirdPartyCookieHeuristic, 'heuristic'));
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(
         undefined, undefined, Protocol.Audits.CookieWarningReason.WarnThirdPartyPhaseout, 'phaseout'));
     await view.updateComplete;
@@ -135,9 +135,9 @@ describeWithMockConnection('CookieReportView', () => {
   it('should only have a single entry for same cookie with a read and a write operations', async () => {
     const view = new Security.CookieReportView.CookieReportView(undefined, mockView);
 
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(true));
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(false));
     await view.updateComplete;
 
@@ -147,7 +147,7 @@ describeWithMockConnection('CookieReportView', () => {
   it('should have zero entries after the primary page was changed', async () => {
     const view = new Security.CookieReportView.CookieReportView(undefined, mockView);
 
-    // @ts-ignore
+    // @ts-expect-error
     globalThis.addIssueForTest(getTestCookieIssue(true));
     await view.updateComplete;
 
diff --git a/front_end/panels/security/SecurityPanelSidebarTreeElement.ts b/front_end/panels/security/SecurityPanelSidebarTreeElement.ts
index 21f067a242..3b2270445a 100644
--- a/front_end/panels/security/SecurityPanelSidebarTreeElement.ts
+++ b/front_end/panels/security/SecurityPanelSidebarTreeElement.ts
@@ -4,7 +4,7 @@
 import * as UI from '../../ui/legacy/legacy.js';
 
 export class SecurityPanelSidebarTreeElement extends UI.TreeOutline.TreeElement {
-  constructor(title: string = '', expandable: boolean = false, jslogContext?: string|number) {
+  constructor(title = '', expandable = false, jslogContext?: string|number) {
     super(title, expandable, jslogContext);
     UI.ARIAUtils.setLabel(this.listItemElement, title);
   }
diff --git a/front_end/panels/settings/SettingsScreen.ts b/front_end/panels/settings/SettingsScreen.ts
index 6b4e530418..dc5a1b0c39 100644
--- a/front_end/panels/settings/SettingsScreen.ts
+++ b/front_end/panels/settings/SettingsScreen.ts
@@ -177,10 +177,6 @@ export class SettingsScreen extends UI.Widget.VBox implements UI.View.ViewLocati
     settingsScreen.show(dialog.contentElement);
     dialog.setEscapeKeyCallback(settingsScreen.onEscapeKeyPressed.bind(settingsScreen));
     dialog.setMarginBehavior(UI.GlassPane.MarginBehavior.NO_MARGIN);
-    // UI.Dialog extends GlassPane and overrides the `show` method with a wider
-    // accepted type. However, TypeScript uses the supertype declaration to
-    // determine the full type, which requires a `!Document`.
-    // @ts-ignore
     dialog.show();
 
     return settingsScreen;
diff --git a/front_end/panels/settings/emulation/components/UserAgentClientHintsForm.ts b/front_end/panels/settings/emulation/components/UserAgentClientHintsForm.ts
index e33710e228..cc0c34f741 100644
--- a/front_end/panels/settings/emulation/components/UserAgentClientHintsForm.ts
+++ b/front_end/panels/settings/emulation/components/UserAgentClientHintsForm.ts
@@ -210,12 +210,12 @@ const DEFAULT_METADATA = {
 export class UserAgentClientHintsForm extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
 
-  #isFormOpened: boolean = false;
-  #isFormDisabled: boolean = false;
+  #isFormOpened = false;
+  #isFormDisabled = false;
   #metaData: Protocol.Emulation.UserAgentMetadata = DEFAULT_METADATA;
-  #showMobileCheckbox: boolean = false;
-  #showSubmitButton: boolean = false;
-  #useragentModifiedAriaMessage: string = '';
+  #showMobileCheckbox = false;
+  #showSubmitButton = false;
+  #useragentModifiedAriaMessage = '';
 
   connectedCallback(): void {
     this.#shadow.adoptedStyleSheets = [Input.checkboxStyles, userAgentClientHintsFormStyles];
diff --git a/front_end/panels/settings/emulation/utils/StructuredHeaders.ts b/front_end/panels/settings/emulation/utils/StructuredHeaders.ts
index 407fd5654b..2f1809ba11 100644
--- a/front_end/panels/settings/emulation/utils/StructuredHeaders.ts
+++ b/front_end/panels/settings/emulation/utils/StructuredHeaders.ts
@@ -146,8 +146,8 @@ const CHAR_PIPE: number = '|'.charCodeAt(0);
 const CHAR_TILDE: number = '~'.charCodeAt(0);
 
 // ASCII printable range.
-const CHAR_MIN_ASCII_PRINTABLE: number = 0x20;
-const CHAR_MAX_ASCII_PRINTABLE: number = 0x7e;
+const CHAR_MIN_ASCII_PRINTABLE = 0x20;
+const CHAR_MAX_ASCII_PRINTABLE = 0x7e;
 
 // Note: structured headers operates over ASCII, not unicode, so these are
 // all indeed supposed to return false on things outside 32-127 range regardless
@@ -415,7 +415,7 @@ function parseParameters(input: Input): Parameters|Error {
 
 // 4.2.3.3.  Parsing a Key
 function parseKey(input: Input): ParamName|Error {
-  let outputString: string = '';
+  let outputString = '';
   const first = input.peekCharCode();
   if (first !== CHAR_STAR && !isLcAlpha(first)) {
     return makeError();
@@ -437,7 +437,7 @@ function parseKey(input: Input): ParamName|Error {
 // 4.2.4.  Parsing an Integer or Decimal
 function parseIntegerOrDecimal(input: Input): Integer|Decimal|Error {
   let resultKind = ResultKind.INTEGER;
-  let sign: number = 1;
+  let sign = 1;
   let inputNumber = '';
   if (input.peek() === '-') {
     input.eat();
diff --git a/front_end/panels/sources/AddSourceMapURLDialog.ts b/front_end/panels/sources/AddSourceMapURLDialog.ts
index 54ced53411..b37a23089a 100644
--- a/front_end/panels/sources/AddSourceMapURLDialog.ts
+++ b/front_end/panels/sources/AddSourceMapURLDialog.ts
@@ -63,10 +63,6 @@ export class AddDebugInfoURLDialog extends UI.Widget.HBox {
 
   override show(): void {
     super.show(this.dialog.contentElement);
-    // UI.Dialog extends GlassPane and overrides the `show` method with a wider
-    // accepted type. However, TypeScript uses the supertype declaration to
-    // determine the full type, which requires a `!Document`.
-    // @ts-ignore
     this.dialog.show();
   }
 
diff --git a/front_end/panels/sources/CSSPlugin.ts b/front_end/panels/sources/CSSPlugin.ts
index 1b64fe9214..41af0e92a7 100644
--- a/front_end/panels/sources/CSSPlugin.ts
+++ b/front_end/panels/sources/CSSPlugin.ts
@@ -463,7 +463,7 @@ export class CSSPlugin extends Plugin implements SDK.TargetManager.SDKModelObser
       override:
           [async(cx: CodeMirror.CompletionContext):
                Promise<CodeMirror.CompletionResult|null> => {
-                 return (await specificCssCompletion(cx, uiSourceCode, cssModel)) || cssCompletionSource(cx);
+                 return await ((await specificCssCompletion(cx, uiSourceCode, cssModel)) || cssCompletionSource(cx));
                }],
     });
   }
diff --git a/front_end/panels/sources/DebuggerPlugin.ts b/front_end/panels/sources/DebuggerPlugin.ts
index c28ad838a7..d8cb82c423 100644
--- a/front_end/panels/sources/DebuggerPlugin.ts
+++ b/front_end/panels/sources/DebuggerPlugin.ts
@@ -205,7 +205,7 @@ export class DebuggerPlugin extends Plugin {
   private executionLocation: Workspace.UISourceCode.UILocation|null = null;
   // Track state of the control key because holding it makes debugger
   // target locations show up in the editor
-  private controlDown: boolean = false;
+  private controlDown = false;
   private controlTimeout: number|undefined = undefined;
   private sourceMapInfobar: UI.Infobar.Infobar|null = null;
   private readonly scriptsPanel: SourcesPanel;
@@ -713,7 +713,7 @@ export class DebuggerPlugin extends Plugin {
     return {
       box,
       show: async (popover: UI.GlassPane.GlassPane) => {
-        let resolvedText: string = '';
+        let resolvedText = '';
         if (selectedCallFrame.script.isJavaScript()) {
           const nameMap = await SourceMapScopes.NamesResolver.allVariablesInCallFrame(selectedCallFrame);
           try {
@@ -2509,20 +2509,20 @@ function lineNumberArrow(color: string, outline: string): string {
       encodeURIComponent(color)}" stroke="${encodeURIComponent(outline)}"/></svg>') 1 3 1 1`;
 }
 
-function inlineBreakpointArrow(color: string, outline: string, opacity: string = '1'): string {
+function inlineBreakpointArrow(color: string, outline: string, opacity = '1'): string {
   return `url('data:image/svg+xml,<svg width="11" height="12" viewBox="0 0 11 12" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M0.5 0.5H5.80139C6.29382 0.5 6.7549 0.741701 7.03503 1.14669L10.392 6L7.03503 10.8533C6.7549 11.2583 6.29382 11.5 5.80139 11.5H0.5V0.5Z" fill="${
       encodeURIComponent(
           color)}" stroke="${encodeURIComponent(outline)}" fill-opacity="${encodeURIComponent(opacity)}"/></svg>')`;
 }
 
-function inlineConditionalBreakpointArrow(color: string, outline: string, opacity: string = '1'): string {
+function inlineConditionalBreakpointArrow(color: string, outline: string, opacity = '1'): string {
   return `url('data:image/svg+xml,<svg width="11" height="12" viewBox="0 0 11 12" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M0.5 0.5H5.80139C6.29382 0.5 6.75489 0.741701 7.03503 1.14669L10.392 6L7.03503 10.8533C6.75489 11.2583 6.29382 11.5 5.80138 11.5H0.5V0.5Z" fill="${
       encodeURIComponent(color)}" fill-opacity="${encodeURIComponent(opacity)}" stroke="${
       encodeURIComponent(
           outline)}"/><path d="M3.51074 7.75635H4.68408V9H3.51074V7.75635ZM4.68408 7.23779H3.51074V6.56104C3.51074 6.271 3.55615 6.02344 3.64697 5.81836C3.73779 5.61328 3.90039 5.39648 4.13477 5.16797L4.53027 4.77686C4.71484 4.59814 4.83936 4.4502 4.90381 4.33301C4.97119 4.21582 5.00488 4.09424 5.00488 3.96826C5.00488 3.77197 4.9375 3.62402 4.80273 3.52441C4.66797 3.4248 4.46582 3.375 4.19629 3.375C3.9502 3.375 3.69238 3.42773 3.42285 3.5332C3.15625 3.63574 2.88232 3.78955 2.60107 3.99463V2.81689C2.88818 2.65283 3.17822 2.52979 3.47119 2.44775C3.76709 2.36279 4.06299 2.32031 4.35889 2.32031C4.95068 2.32031 5.41504 2.45801 5.75195 2.7334C6.08887 3.00879 6.25732 3.38818 6.25732 3.87158C6.25732 4.09424 6.20752 4.30225 6.10791 4.49561C6.0083 4.68604 5.8208 4.91602 5.54541 5.18555L5.15869 5.56348C4.95947 5.75684 4.83203 5.91504 4.77637 6.03809C4.7207 6.16113 4.69287 6.31201 4.69287 6.49072C4.69287 6.51709 4.69141 6.54785 4.68848 6.58301C4.68848 6.61816 4.68701 6.65625 4.68408 6.69727V7.23779Z" fill="white"/></svg>')`;
 }
 
-function inlineLogpointArrow(color: string, outline: string, opacity: string = '1'): string {
+function inlineLogpointArrow(color: string, outline: string, opacity = '1'): string {
   return `url('data:image/svg+xml,<svg width="11" height="12" viewBox="0 0 11 12" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M0.5 0.5H5.80139C6.29382 0.5 6.7549 0.741701 7.03503 1.14669L10.392 6L7.03503 10.8533C6.7549 11.2583 6.29382 11.5 5.80139 11.5H0.5V0.5Z" fill="${
       encodeURIComponent(color)}" stroke="${encodeURIComponent(outline)}" fill-opacity="${
       encodeURIComponent(
diff --git a/front_end/panels/sources/NavigatorView.ts b/front_end/panels/sources/NavigatorView.ts
index f0d78b6940..fed802a153 100644
--- a/front_end/panels/sources/NavigatorView.ts
+++ b/front_end/panels/sources/NavigatorView.ts
@@ -1906,7 +1906,6 @@ export class NavigatorFolderTreeNode extends NavigatorTreeNode {
   }
 
   override wasPopulated(): void {
-    // @ts-ignore These types are invalid, but removing this check causes wrong behavior
     if (!this.treeElement || this.treeElement.node !== this) {
       return;
     }
diff --git a/front_end/panels/sources/OutlineQuickOpen.ts b/front_end/panels/sources/OutlineQuickOpen.ts
index 4190db3ceb..be58a7d39a 100644
--- a/front_end/panels/sources/OutlineQuickOpen.ts
+++ b/front_end/panels/sources/OutlineQuickOpen.ts
@@ -268,7 +268,7 @@ export function outline(state: CodeMirror.EditorState): OutlineItem[] {
 
 export class OutlineQuickOpen extends QuickOpen.FilteredListWidget.Provider {
   private items: OutlineItem[] = [];
-  private active: boolean = false;
+  private active = false;
 
   constructor() {
     super('source-symbol');
diff --git a/front_end/panels/sources/SourcesPanel.ts b/front_end/panels/sources/SourcesPanel.ts
index cc0afa819f..871c681cd6 100644
--- a/front_end/panels/sources/SourcesPanel.ts
+++ b/front_end/panels/sources/SourcesPanel.ts
@@ -1313,7 +1313,7 @@ export class DebuggerPausedDetailsRevealer implements
     Common.Revealer.Revealer<SDK.DebuggerModel.DebuggerPausedDetails> {
   async reveal(_object: SDK.DebuggerModel.DebuggerPausedDetails): Promise<void> {
     if (Common.Settings.Settings.instance().moduleSetting('auto-focus-on-debugger-paused-enabled').get()) {
-      return SourcesPanel.instance().setAsCurrentPanel();
+      return await SourcesPanel.instance().setAsCurrentPanel();
     }
   }
 }
diff --git a/front_end/panels/sources/UISourceCodeFrame.ts b/front_end/panels/sources/UISourceCodeFrame.ts
index 04e5301a5c..4c6c1b83d5 100644
--- a/front_end/panels/sources/UISourceCodeFrame.ts
+++ b/front_end/panels/sources/UISourceCodeFrame.ts
@@ -110,7 +110,7 @@ export class UISourceCodeFrame extends
     if (this.uiSourceCodeInternal.isDirty()) {
       return this.uiSourceCodeInternal.workingCopyContentData();
     }
-    return this.uiSourceCodeInternal.requestContentData();
+    return await this.uiSourceCodeInternal.requestContentData();
   }
 
   protected override editorConfiguration(doc: string): CodeMirror.Extension {
diff --git a/front_end/panels/sources/WatchExpressionsSidebarPane.ts b/front_end/panels/sources/WatchExpressionsSidebarPane.ts
index 369a65d163..f01b63fb15 100644
--- a/front_end/panels/sources/WatchExpressionsSidebarPane.ts
+++ b/front_end/panels/sources/WatchExpressionsSidebarPane.ts
@@ -351,7 +351,7 @@ export class WatchExpression extends Common.ObjectWrapper.ObjectWrapper<EventTyp
       }
     }
 
-    return executionContext.evaluate(
+    return await executionContext.evaluate(
         {
           expression,
           objectGroup: WatchExpression.watchObjectGroupId,
diff --git a/front_end/panels/sources/components/BreakpointsView.test.ts b/front_end/panels/sources/components/BreakpointsView.test.ts
index 39df3bb32b..00640922df 100644
--- a/front_end/panels/sources/components/BreakpointsView.test.ts
+++ b/front_end/panels/sources/components/BreakpointsView.test.ts
@@ -104,9 +104,9 @@ function createStubBreakpointManagerAndSettingsWithMockdata(testData: LocationTe
 }
 
 function createLocationTestData(
-    url: string, lineNumber: number, columnNumber: number, enabled: boolean = true, content: string = '',
+    url: string, lineNumber: number, columnNumber: number, enabled = true, content = '',
     condition: Breakpoints.BreakpointManager.UserCondition = Breakpoints.BreakpointManager.EMPTY_BREAKPOINT_CONDITION,
-    isLogpoint: boolean = false, hoverText?: string): LocationTestData {
+    isLogpoint = false, hoverText?: string): LocationTestData {
   return {
     url: urlString`${url}`,
     lineNumber,
@@ -1207,7 +1207,7 @@ describeWithMockConnection('BreakpointsView', () => {
   describe('group checkboxes', () => {
     async function waitForCheckboxToggledEventsWithCheckedUpdate(
         component: SourcesComponents.BreakpointsView.BreakpointsView, numBreakpointItems: number, checked: boolean) {
-      return new Promise<void>(resolve => {
+      return await new Promise<void>(resolve => {
         let numCheckboxToggledEvents = 0;
         const controller = SourcesComponents.BreakpointsView.BreakpointsSidebarController.instance();
         sinon.stub(controller, 'breakpointStateChanged').callsFake((_, checkedArg) => {
diff --git a/front_end/panels/sources/components/BreakpointsView.ts b/front_end/panels/sources/components/BreakpointsView.ts
index 5bb2d5d6dc..1ac250468e 100644
--- a/front_end/panels/sources/components/BreakpointsView.ts
+++ b/front_end/panels/sources/components/BreakpointsView.ts
@@ -539,13 +539,13 @@ export class BreakpointsView extends LegacyWrapper.LegacyWrapper.WrappableCompon
 
   readonly #shadow = this.attachShadow({mode: 'open'});
 
-  #pauseOnUncaughtExceptions: boolean = false;
-  #pauseOnCaughtExceptions: boolean = false;
+  #pauseOnUncaughtExceptions = false;
+  #pauseOnCaughtExceptions = false;
 
   // TODO(crbug.com/1382762): Remove special casing with dependent toggles as soon as Node LTS caught up on independent pause of exception toggles.
-  #independentPauseToggles: boolean = false;
+  #independentPauseToggles = false;
 
-  #breakpointsActive: boolean = true;
+  #breakpointsActive = true;
   #breakpointGroups: BreakpointGroup[] = [];
   #urlToDifferentiatingPath = new Map<Platform.DevToolsPath.UrlString, string>();
 
@@ -633,11 +633,11 @@ export class BreakpointsView extends LegacyWrapper.LegacyWrapper.WrappableCompon
 
     if (event.key === 'Home' || event.key === 'End') {
       event.consume(true);
-      return this.#handleHomeOrEndKey(event.key);
+      return await this.#handleHomeOrEndKey(event.key);
     }
     if (Platform.KeyboardUtilities.keyIsArrowKey(event.key)) {
       event.consume(true);
-      return this.#handleArrowKey(event.key, event.target);
+      return await this.#handleArrowKey(event.key, event.target);
     }
     if (Platform.KeyboardUtilities.isEnterOrSpaceKey(event)) {
       const currentTarget = event.currentTarget as HTMLElement;
@@ -675,19 +675,19 @@ export class BreakpointsView extends LegacyWrapper.LegacyWrapper.WrappableCompon
       });
     };
     const nextNode = await findNextNodeForKeyboardNavigation(target, key, setGroupExpandedState);
-    return this.#setSelected(nextNode);
+    return await this.#setSelected(nextNode);
   }
 
   async #handleHomeOrEndKey(key: 'Home'|'End'): Promise<void> {
     if (key === 'Home') {
       const pauseOnExceptionsNode = this.#shadow.querySelector<HTMLElement>('[data-first-pause]');
-      return this.#setSelected(pauseOnExceptionsNode);
+      return await this.#setSelected(pauseOnExceptionsNode);
     }
     if (key === 'End') {
       const numGroups = this.#breakpointGroups.length;
       if (numGroups === 0) {
         const lastPauseOnExceptionsNode = this.#shadow.querySelector<HTMLElement>('[data-last-pause]');
-        return this.#setSelected(lastPauseOnExceptionsNode);
+        return await this.#setSelected(lastPauseOnExceptionsNode);
       }
       const lastGroupIndex = numGroups - 1;
       const lastGroup = this.#breakpointGroups[lastGroupIndex];
@@ -695,10 +695,10 @@ export class BreakpointsView extends LegacyWrapper.LegacyWrapper.WrappableCompon
       if (lastGroup.expanded) {
         const lastBreakpointItem =
             this.#shadow.querySelector<HTMLElement>('[data-last-group] > [data-last-breakpoint]');
-        return this.#setSelected(lastBreakpointItem);
+        return await this.#setSelected(lastBreakpointItem);
       }
       const lastGroupSummaryElement = this.#shadow.querySelector<HTMLElement>('[data-last-group] > summary');
-      return this.#setSelected(lastGroupSummaryElement);
+      return await this.#setSelected(lastGroupSummaryElement);
     }
     return;
   }
diff --git a/front_end/panels/timeline/CountersGraph.ts b/front_end/panels/timeline/CountersGraph.ts
index 8ef01272b3..de82d4a3a3 100644
--- a/front_end/panels/timeline/CountersGraph.ts
+++ b/front_end/panels/timeline/CountersGraph.ts
@@ -94,7 +94,7 @@ export class CountersGraph extends UI.Widget.VBox {
   #onTraceBoundsChangeBound = this.#onTraceBoundsChange.bind(this);
 
   #noEventsFoundMessage = document.createElement('div');
-  #showNoEventsMessage: boolean = false;
+  #showNoEventsMessage = false;
 
   constructor(delegate: TimelineModeViewDelegate) {
     super();
@@ -254,7 +254,7 @@ export class CountersGraph extends UI.Widget.VBox {
 
   private onClick(event: Event): void {
     const x = (event as MouseEvent).x - this.canvasContainer.getBoundingClientRect().left;
-    let minDistance: number = Infinity;
+    let minDistance = Infinity;
     let bestTime;
     for (const counterUI of this.counterUI) {
       if (!counterUI.counter.times.length) {
diff --git a/front_end/panels/timeline/ModificationsManager.ts b/front_end/panels/timeline/ModificationsManager.ts
index 551758e493..5b87129e7e 100644
--- a/front_end/panels/timeline/ModificationsManager.ts
+++ b/front_end/panels/timeline/ModificationsManager.ts
@@ -133,7 +133,7 @@ export class ModificationsManager extends EventTarget {
     }
   }
 
-  createAnnotation(newAnnotation: Trace.Types.File.Annotation, loadedFromFile: boolean = false): void {
+  createAnnotation(newAnnotation: Trace.Types.File.Annotation, loadedFromFile = false): void {
     // If a label already exists on an entry and a user is trying to create a new one, start editing an existing label instead.
     if (newAnnotation.type === 'ENTRY_LABEL') {
       const overlay = this.#findLabelOverlayForEntry(newAnnotation.entry);
diff --git a/front_end/panels/timeline/ThreadAppender.ts b/front_end/panels/timeline/ThreadAppender.ts
index c3d853f428..8f605eec78 100644
--- a/front_end/panels/timeline/ThreadAppender.ts
+++ b/front_end/panels/timeline/ThreadAppender.ts
@@ -152,11 +152,11 @@ export class ThreadAppender implements TrackAppender {
   #threadId: Trace.Types.Events.ThreadID;
   #threadDefaultName: string;
   #expanded = false;
-  #headerAppended: boolean = false;
+  #headerAppended = false;
   readonly threadType: Trace.Handlers.Threads.ThreadType = Trace.Handlers.Threads.ThreadType.MAIN_THREAD;
   readonly isOnMainFrame: boolean;
   #showAllEventsEnabled = Root.Runtime.experiments.isEnabled('timeline-show-all-events');
-  #url: string = '';
+  #url = '';
   #headerNestingLevel: number|null = null;
   constructor(
       compatibilityBuilder: CompatibilityTracksAppender, parsedTrace: Trace.Handlers.Types.ParsedTrace,
@@ -212,7 +212,7 @@ export class ThreadAppender implements TrackAppender {
    * @returns the first available level to append more data after having
    * appended the track's events.
    */
-  appendTrackAtLevel(trackStartLevel: number, expanded: boolean = false): number {
+  appendTrackAtLevel(trackStartLevel: number, expanded = false): number {
     if (this.#entries.length === 0) {
       return trackStartLevel;
     }
@@ -460,7 +460,7 @@ export class ThreadAppender implements TrackAppender {
    */
   #appendNodesAtLevel(
       nodes: Iterable<Trace.Helpers.TreeHelpers.TraceEntryNode>, startingLevel: number,
-      parentIsIgnoredListed: boolean = false): number {
+      parentIsIgnoredListed = false): number {
     const invisibleEntries =
         ModificationsManager.ModificationsManager.activeManager()?.getEntriesFilter().invisibleEntries() ?? [];
     let maxDepthInTree = startingLevel;
diff --git a/front_end/panels/timeline/TimelineController.ts b/front_end/panels/timeline/TimelineController.ts
index 4d5c57dd94..ec40972fa7 100644
--- a/front_end/panels/timeline/TimelineController.ts
+++ b/front_end/panels/timeline/TimelineController.ts
@@ -194,7 +194,7 @@ export class TimelineController implements Trace.TracingManager.TracingManagerCl
     }
 
     const urls = [...new Set(this.#navigationUrls)];
-    return Promise.all(urls.map(url => cruxManager.getFieldDataForPage(url)));
+    return await Promise.all(urls.map(url => cruxManager.getFieldDataForPage(url)));
   }
 
   private async createMetadata(): Promise<Trace.Types.File.MetaData> {
@@ -205,7 +205,7 @@ export class TimelineController implements Trace.TracingManager.TracingManagerCl
     } else if (deviceModeModel?.type() === EmulationModel.DeviceModeModel.Type.Responsive) {
       emulatedDeviceTitle = 'Responsive';
     }
-    return Trace.Extras.Metadata.forNewRecording(
+    return await Trace.Extras.Metadata.forNewRecording(
         false, this.#recordingStartTime ?? undefined, emulatedDeviceTitle, this.#fieldData ?? undefined);
   }
 
diff --git a/front_end/panels/timeline/TimelineDetailsView.ts b/front_end/panels/timeline/TimelineDetailsView.ts
index b3472d6bbd..caaa5736c2 100644
--- a/front_end/panels/timeline/TimelineDetailsView.ts
+++ b/front_end/panels/timeline/TimelineDetailsView.ts
@@ -316,7 +316,7 @@ export class TimelineDetailsPane extends
    * debounced. The forceImmediateUpdate param configures the debouncing
    * behaviour.
    */
-  private scheduleUpdateContentsFromWindow(forceImmediateUpdate: boolean = false): void {
+  private scheduleUpdateContentsFromWindow(forceImmediateUpdate = false): void {
     if (!this.#parsedTrace) {
       this.setSummaryContent(UI.Fragment.html`<div/>`);
       return;
diff --git a/front_end/panels/timeline/TimelineEventOverview.ts b/front_end/panels/timeline/TimelineEventOverview.ts
index a094218522..72a4dd377d 100644
--- a/front_end/panels/timeline/TimelineEventOverview.ts
+++ b/front_end/panels/timeline/TimelineEventOverview.ts
@@ -454,7 +454,7 @@ export class TimelineFilmStripOverview extends TimelineEventOverview {
       imagePromise = UI.UIUtils.loadImage(uri);
       this.frameToImagePromise.set(frame, (imagePromise as Promise<HTMLImageElement>));
     }
-    return imagePromise;
+    return await imagePromise;
   }
 
   private drawFrames(
diff --git a/front_end/panels/timeline/TimelineFlameChartDataProvider.ts b/front_end/panels/timeline/TimelineFlameChartDataProvider.ts
index c771cb8dca..c552ff73f0 100644
--- a/front_end/panels/timeline/TimelineFlameChartDataProvider.ts
+++ b/front_end/panels/timeline/TimelineFlameChartDataProvider.ts
@@ -114,8 +114,8 @@ export class TimelineFlameChartDataProvider extends Common.ObjectWrapper.ObjectW
   private compatibilityTracksAppender: CompatibilityTracksAppender|null = null;
   private parsedTrace: Trace.Handlers.Types.ParsedTrace|null = null;
 
-  #minimumBoundary: number = 0;
-  private timeSpan: number = 0;
+  #minimumBoundary = 0;
+  private timeSpan = 0;
   private readonly framesGroupStyle: PerfUI.FlameChart.GroupStyle;
   private readonly screenshotsGroupStyle: PerfUI.FlameChart.GroupStyle;
 
@@ -132,7 +132,7 @@ export class TimelineFlameChartDataProvider extends Common.ObjectWrapper.ObjectW
 
   private entryTypeByLevel: EntryType[] = [];
   private entryIndexToTitle: string[] = [];
-  private lastInitiatorEntry: number = -1;
+  private lastInitiatorEntry = -1;
   private lastInitiatorsData: PerfUI.FlameChart.FlameChartInitiatorData[] = [];
 
   private lastSelection: Selection|null = null;
@@ -553,7 +553,7 @@ export class TimelineFlameChartDataProvider extends Common.ObjectWrapper.ObjectW
    * Builds the flame chart data using the tracks appender (which use
    * the new trace engine). The result built data is cached and returned.
    */
-  timelineData(rebuild: boolean = false): PerfUI.FlameChart.FlameChartTimelineData {
+  timelineData(rebuild = false): PerfUI.FlameChart.FlameChartTimelineData {
     if (!rebuild && this.timelineDataInternal && this.timelineDataInternal.entryLevels.length !== 0) {
       // If the flame chart data is built already and we don't want to rebuild, we can return the cached data.
       // |entryLevels.length| is used to check if the cached data is not empty (correctly built),
diff --git a/front_end/panels/timeline/TimelineFlameChartNetworkDataProvider.ts b/front_end/panels/timeline/TimelineFlameChartNetworkDataProvider.ts
index 6e10177604..9eba33f06b 100644
--- a/front_end/panels/timeline/TimelineFlameChartNetworkDataProvider.ts
+++ b/front_end/panels/timeline/TimelineFlameChartNetworkDataProvider.ts
@@ -25,10 +25,10 @@ import {
 import * as TimelineUtils from './utils/utils.js';
 
 export class TimelineFlameChartNetworkDataProvider implements PerfUI.FlameChart.FlameChartDataProvider {
-  #minimumBoundary: number = 0;
-  #timeSpan: number = 0;
+  #minimumBoundary = 0;
+  #timeSpan = 0;
   #events: NetworkTrackEvent[] = [];
-  #maxLevel: number = 0;
+  #maxLevel = 0;
   #networkTrackAppender: NetworkTrackAppender|null = null;
 
   #timelineDataInternal: PerfUI.FlameChart.FlameChartTimelineData|null = null;
@@ -36,7 +36,7 @@ export class TimelineFlameChartNetworkDataProvider implements PerfUI.FlameChart.
   #parsedTrace: Trace.Handlers.Types.ParsedTrace|null = null;
   #eventIndexByEvent = new Map<NetworkTrackEvent, number|null>();
   // -1 means no entry is selected.
-  #lastInitiatorEntry: number = -1;
+  #lastInitiatorEntry = -1;
   #lastInitiatorsData: PerfUI.FlameChart.FlameChartInitiatorData[] = [];
   #entityMapper: TimelineUtils.EntityMapper.EntityMapper|null = null;
 
diff --git a/front_end/panels/timeline/TimelineLoader.ts b/front_end/panels/timeline/TimelineLoader.ts
index c7a3773eea..8baa20178d 100644
--- a/front_end/panels/timeline/TimelineLoader.ts
+++ b/front_end/panels/timeline/TimelineLoader.ts
@@ -202,7 +202,7 @@ export class TimelineLoader implements Common.StringOutputStream.OutputStream {
    */
   async write(chunk: string, endOfFile: boolean): Promise<void> {
     if (!this.client) {
-      return Promise.resolve();
+      return await Promise.resolve();
     }
     this.buffer += chunk;
     if (this.firstRawChunk) {
@@ -224,11 +224,10 @@ export class TimelineLoader implements Common.StringOutputStream.OutputStream {
       try {
         trace = JSON.parse(this.buffer) as ParsedJSONFile;
         this.#processParsedFile(trace);
-        return Promise.resolve();
       } catch (e) {
         this.reportErrorAndCancelLoading(i18nString(UIStrings.malformedTimelineDataS, {PH1: e.toString()}));
-        return;
       }
+      return;
     }
   }
 
diff --git a/front_end/panels/timeline/TimelineMiniMap.ts b/front_end/panels/timeline/TimelineMiniMap.ts
index ed4b166686..9b060d3c34 100644
--- a/front_end/panels/timeline/TimelineMiniMap.ts
+++ b/front_end/panels/timeline/TimelineMiniMap.ts
@@ -203,7 +203,7 @@ export class TimelineMiniMap extends
     };
   }
 
-  highlightBounds(bounds: Trace.Types.Timing.TraceWindowMicro, withBracket: boolean = false): void {
+  highlightBounds(bounds: Trace.Types.Timing.TraceWindowMicro, withBracket = false): void {
     this.#overviewComponent.highlightBounds(bounds, withBracket);
   }
   clearBoundsHighlight(): void {
diff --git a/front_end/panels/timeline/TimelinePaintProfilerView.ts b/front_end/panels/timeline/TimelinePaintProfilerView.ts
index a0ff2a9f8c..c25bf0a73d 100644
--- a/front_end/panels/timeline/TimelinePaintProfilerView.ts
+++ b/front_end/panels/timeline/TimelinePaintProfilerView.ts
@@ -134,7 +134,7 @@ export class TimelinePaintProfilerView extends UI.SplitWidget.SplitWidget {
         frame.layerTree,
     );
     const tracingLayerTree = await layerTree.layerTreePromise();
-    return tracingLayerTree ? tracingLayerTree.pictureForRasterTile(data.tileId.id_ref) : null;
+    return tracingLayerTree ? await tracingLayerTree.pictureForRasterTile(data.tileId.id_ref) : null;
   }
 
   update(): void {
diff --git a/front_end/panels/timeline/TimelinePanel.ts b/front_end/panels/timeline/TimelinePanel.ts
index d1db923b03..c16894f69d 100644
--- a/front_end/panels/timeline/TimelinePanel.ts
+++ b/front_end/panels/timeline/TimelinePanel.ts
@@ -460,7 +460,7 @@ export class TimelinePanel extends UI.Panel.Panel implements Client, TimelineMod
    * (status pane, landing page, trace view) into distinct components /
    * widgets, to avoid this complexity.
    */
-  #restoreSidebarVisibilityOnTraceLoad: boolean = false;
+  #restoreSidebarVisibilityOnTraceLoad = false;
 
   /**
    * Used to track an aria announcement that we need to alert for
@@ -1349,7 +1349,7 @@ export class TimelinePanel extends UI.Panel.Panel implements Client, TimelineMod
     void contextMenu.show();
   }
 
-  async saveToFile(isEnhancedTraces: boolean = false, addModifications: boolean = false): Promise<void> {
+  async saveToFile(isEnhancedTraces = false, addModifications = false): Promise<void> {
     if (this.state !== State.IDLE) {
       return;
     }
@@ -2420,7 +2420,7 @@ export class TimelinePanel extends UI.Panel.Panel implements Client, TimelineMod
   async #executeNewTrace(
       collectedEvents: Trace.Types.Events.Event[], isFreshRecording: boolean,
       metadata: Trace.Types.File.MetaData|null): Promise<void> {
-    return this.#traceEngineModel.parse(
+    return await this.#traceEngineModel.parse(
         collectedEvents,
         {
           metadata: metadata ?? undefined,
diff --git a/front_end/panels/timeline/TimelineUIUtils.ts b/front_end/panels/timeline/TimelineUIUtils.ts
index 43efd40729..30aba5149a 100644
--- a/front_end/panels/timeline/TimelineUIUtils.ts
+++ b/front_end/panels/timeline/TimelineUIUtils.ts
@@ -1060,7 +1060,7 @@ export class TimelineUIUtils {
     );
 
     if (maybeTarget) {
-      // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+      // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
       if (typeof event[previewElementSymbol] === 'undefined') {
         let previewElement: (Element|null)|null = null;
         const url = Trace.Handlers.Helpers.getNonResolvedURL(event, parsedTrace);
@@ -1073,7 +1073,7 @@ export class TimelineUIUtils {
         } else if (Trace.Types.Events.isPaint(event)) {
           previewElement = await TimelineUIUtils.buildPicturePreviewContent(parsedTrace, event, maybeTarget);
         }
-        // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+        // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
         event[previewElementSymbol] = previewElement;
       }
     }
@@ -1274,7 +1274,7 @@ export class TimelineUIUtils {
         break;
       }
 
-      // @ts-ignore Fall-through intended.
+      // @ts-expect-error Fall-through intended.
       case Trace.Types.Events.Name.PAINT: {
         const clip = unsafeEventData['clip'];
         contentHelper.appendTextRow(
@@ -1484,7 +1484,7 @@ export class TimelineUIUtils {
         break;
       }
 
-      // @ts-ignore Fall-through intended.
+      // @ts-expect-error Fall-through intended.
       case Trace.Types.Events.Name.FIRE_IDLE_CALLBACK: {
         contentHelper.appendTextRow(
             i18nString(UIStrings.allottedTime),
@@ -1503,7 +1503,7 @@ export class TimelineUIUtils {
         break;
       }
 
-      // @ts-ignore Fall-through intended.
+      // @ts-expect-error Fall-through intended.
       case Trace.Types.Events.Name.MARK_LCP_CANDIDATE: {
         contentHelper.appendTextRow(i18nString(UIStrings.type), String(unsafeEventData['type']));
         contentHelper.appendTextRow(i18nString(UIStrings.size), String(unsafeEventData['size']));
@@ -1564,10 +1564,10 @@ export class TimelineUIUtils {
       }
     }
 
-    // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+    // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
     if (event[previewElementSymbol]) {
       contentHelper.addSection(i18nString(UIStrings.preview));
-      // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+      // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
       contentHelper.appendElementRow('', event[previewElementSymbol]);
     }
 
@@ -1615,7 +1615,7 @@ export class TimelineUIUtils {
 
     function aggregatedStatsAtTime(time: number): TimeRangeCategoryStats {
       const stats: TimeRangeCategoryStats = {};
-      // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+      // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
       const cache = events[categoryBreakdownCacheSymbol];
       for (const category in cache) {
         const categoryCache = cache[category];
@@ -1647,7 +1647,7 @@ export class TimelineUIUtils {
     }
 
     function buildRangeStatsCacheIfNeeded(events: Trace.Types.Events.Event[]): void {
-      // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+      // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
       if (events[categoryBreakdownCacheSymbol]) {
         return;
       }
@@ -1715,7 +1715,7 @@ export class TimelineUIUtils {
       }
 
       const obj = (events as Object);
-      // @ts-ignore TODO(crbug.com/1011811): Remove symbol usage.
+      // @ts-expect-error TODO(crbug.com/1011811): Remove symbol usage.
       obj[categoryBreakdownCacheSymbol] = aggregatedStats;
     }
   }
@@ -2357,7 +2357,7 @@ export class TimelineUIUtils {
     return colorGenerator.colorForID(id);
   }
 
-  static displayNameForFrame(frame: Trace.Types.Events.TraceFrame, trimAt: number = 80): string {
+  static displayNameForFrame(frame: Trace.Types.Events.TraceFrame, trimAt = 80): string {
     const url = frame.url as Platform.DevToolsPath.UrlString;
     return Common.ParsedURL.schemeIs(url, 'about:') ? `"${Platform.StringUtilities.trimMiddle(frame.name, trimAt)}"` :
                                                       frame.url.slice(0, trimAt);
diff --git a/front_end/panels/timeline/TracingLayerTree.ts b/front_end/panels/timeline/TracingLayerTree.ts
index 208834136a..6bd8c86537 100644
--- a/front_end/panels/timeline/TracingLayerTree.ts
+++ b/front_end/panels/timeline/TracingLayerTree.ts
@@ -328,7 +328,7 @@ export class TracingLayer implements SDK.LayerTreeBase.Layer {
   }
 
   async pictureForRect(targetRect: number[]): Promise<SDK.PaintProfiler.SnapshotWithRect|null> {
-    return Promise.all(this.paints.map(paint => paint.picture())).then(pictures => {
+    return await Promise.all(this.paints.map(paint => paint.picture())).then(pictures => {
       const filteredPictures = (pictures.filter(picture => picture && rectsOverlap(picture.rect, targetRect)) as Array<{
                                   rect: number[],
                                   serializedPicture: string,
diff --git a/front_end/panels/timeline/components/FieldSettingsDialog.ts b/front_end/panels/timeline/components/FieldSettingsDialog.ts
index f8d78f8543..4bd512ffbc 100644
--- a/front_end/panels/timeline/components/FieldSettingsDialog.ts
+++ b/front_end/panels/timeline/components/FieldSettingsDialog.ts
@@ -112,8 +112,8 @@ export class FieldSettingsDialog extends HTMLElement {
 
   #configSetting = CrUXManager.CrUXManager.instance().getConfigSetting();
 
-  #urlOverride: string = '';
-  #urlOverrideEnabled: boolean = false;
+  #urlOverride = '';
+  #urlOverrideEnabled = false;
   #urlOverrideWarning = '';
   #originMap?: OriginMap;
 
diff --git a/front_end/panels/timeline/components/LiveMetricsView.ts b/front_end/panels/timeline/components/LiveMetricsView.ts
index 433b1c00e9..3707847121 100644
--- a/front_end/panels/timeline/components/LiveMetricsView.ts
+++ b/front_end/panels/timeline/components/LiveMetricsView.ts
@@ -300,7 +300,7 @@ const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
 export class LiveMetricsView extends LegacyWrapper.LegacyWrapper.WrappableComponent {
   readonly #shadow = this.attachShadow({mode: 'open'});
 
-  #isNode: boolean = false;
+  #isNode = false;
 
   #lcpValue?: LiveMetrics.LcpValue;
   #clsValue?: LiveMetrics.ClsValue;
diff --git a/front_end/panels/timeline/components/insights/CLSCulprits.ts b/front_end/panels/timeline/components/insights/CLSCulprits.ts
index cf7b0f0cdb..bf2cdbc2b2 100644
--- a/front_end/panels/timeline/components/insights/CLSCulprits.ts
+++ b/front_end/panels/timeline/components/insights/CLSCulprits.ts
@@ -17,7 +17,7 @@ const {html} = Lit;
 
 export class CLSCulprits extends BaseInsightComponent<CLSCulpritsInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-cls-culprits`;
-  override internalName: string = 'cls-culprits';
+  override internalName = 'cls-culprits';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     const clustersByScore =
diff --git a/front_end/panels/timeline/components/insights/DOMSize.ts b/front_end/panels/timeline/components/insights/DOMSize.ts
index ebfd541b62..e122686adf 100644
--- a/front_end/panels/timeline/components/insights/DOMSize.ts
+++ b/front_end/panels/timeline/components/insights/DOMSize.ts
@@ -21,7 +21,7 @@ const {html} = Lit;
 
 export class DOMSize extends BaseInsightComponent<DOMSizeInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-dom-size`;
-  override internalName: string = 'dom-size';
+  override internalName = 'dom-size';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     if (!this.model) {
diff --git a/front_end/panels/timeline/components/insights/DocumentLatency.ts b/front_end/panels/timeline/components/insights/DocumentLatency.ts
index a527e6cbdf..677795dfdc 100644
--- a/front_end/panels/timeline/components/insights/DocumentLatency.ts
+++ b/front_end/panels/timeline/components/insights/DocumentLatency.ts
@@ -17,7 +17,7 @@ const {html} = Lit;
 
 export class DocumentLatency extends BaseInsightComponent<DocumentLatencyInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-document-latency`;
-  override internalName: string = 'document-latency';
+  override internalName = 'document-latency';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     if (!this.model?.data?.documentRequest) {
diff --git a/front_end/panels/timeline/components/insights/FontDisplay.ts b/front_end/panels/timeline/components/insights/FontDisplay.ts
index edfb7d6bbd..7784ef0f7b 100644
--- a/front_end/panels/timeline/components/insights/FontDisplay.ts
+++ b/front_end/panels/timeline/components/insights/FontDisplay.ts
@@ -20,7 +20,7 @@ const {html} = Lit;
 
 export class FontDisplay extends BaseInsightComponent<FontDisplayInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-font-display`;
-  override internalName: string = 'font-display';
+  override internalName = 'font-display';
 
   #overlayForRequest = new Map<Trace.Types.Events.SyntheticNetworkRequest, Overlays.Overlays.TimelineOverlay>();
 
diff --git a/front_end/panels/timeline/components/insights/ForcedReflow.ts b/front_end/panels/timeline/components/insights/ForcedReflow.ts
index 74ded4a80d..f28574145d 100644
--- a/front_end/panels/timeline/components/insights/ForcedReflow.ts
+++ b/front_end/panels/timeline/components/insights/ForcedReflow.ts
@@ -22,7 +22,7 @@ const {html} = Lit;
 
 export class ForcedReflow extends BaseInsightComponent<ForcedReflowInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-forced-reflow`;
-  override internalName: string = 'forced-reflow';
+  override internalName = 'forced-reflow';
 
   #linkifyUrl(callFrame: Trace.Types.Events.CallFrame|Protocol.Runtime.CallFrame): Lit.LitTemplate {
     const linkifier = new LegacyComponents.Linkifier.Linkifier();
diff --git a/front_end/panels/timeline/components/insights/ImageDelivery.ts b/front_end/panels/timeline/components/insights/ImageDelivery.ts
index bcc61ee5ed..cbbb58e7ae 100644
--- a/front_end/panels/timeline/components/insights/ImageDelivery.ts
+++ b/front_end/panels/timeline/components/insights/ImageDelivery.ts
@@ -22,7 +22,7 @@ const MAX_REQUESTS = 10;
 
 export class ImageDelivery extends BaseInsightComponent<ImageDeliveryInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-image-delivery`;
-  override internalName: string = 'image-delivery';
+  override internalName = 'image-delivery';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     if (!this.model) {
diff --git a/front_end/panels/timeline/components/insights/InteractionToNextPaint.ts b/front_end/panels/timeline/components/insights/InteractionToNextPaint.ts
index 842bedb889..ca6023fae8 100644
--- a/front_end/panels/timeline/components/insights/InteractionToNextPaint.ts
+++ b/front_end/panels/timeline/components/insights/InteractionToNextPaint.ts
@@ -19,7 +19,7 @@ const {html} = Lit;
 
 export class InteractionToNextPaint extends BaseInsightComponent<INPInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-inp`;
-  override internalName: string = 'inp';
+  override internalName = 'inp';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     if (!this.model) {
diff --git a/front_end/panels/timeline/components/insights/LCPDiscovery.ts b/front_end/panels/timeline/components/insights/LCPDiscovery.ts
index 4a46aacf14..e87b41f9ad 100644
--- a/front_end/panels/timeline/components/insights/LCPDiscovery.ts
+++ b/front_end/panels/timeline/components/insights/LCPDiscovery.ts
@@ -61,7 +61,7 @@ function getImageData(model: LCPDiscoveryInsightModel): LCPImageDiscoveryData|nu
 
 export class LCPDiscovery extends BaseInsightComponent<LCPDiscoveryInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-lcp-discovery`;
-  override internalName: string = 'lcp-discovery';
+  override internalName = 'lcp-discovery';
 
   #renderDiscoveryDelay(delay: Trace.Types.Timing.Micro): Element {
     const timeWrapper = document.createElement('span');
diff --git a/front_end/panels/timeline/components/insights/LCPPhases.ts b/front_end/panels/timeline/components/insights/LCPPhases.ts
index 298e45fd13..e14c6eadbb 100644
--- a/front_end/panels/timeline/components/insights/LCPPhases.ts
+++ b/front_end/panels/timeline/components/insights/LCPPhases.ts
@@ -24,7 +24,7 @@ interface PhaseData {
 
 export class LCPPhases extends BaseInsightComponent<LCPPhasesInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-lcp-by-phases`;
-  override internalName: string = 'lcp-by-phase';
+  override internalName = 'lcp-by-phase';
   #overlay: Overlays.Overlays.TimespanBreakdown|null = null;
 
   #getPhaseData(): PhaseData[] {
diff --git a/front_end/panels/timeline/components/insights/NetworkDependencyTree.ts b/front_end/panels/timeline/components/insights/NetworkDependencyTree.ts
index 33e7cc29d4..abb45ccad1 100644
--- a/front_end/panels/timeline/components/insights/NetworkDependencyTree.ts
+++ b/front_end/panels/timeline/components/insights/NetworkDependencyTree.ts
@@ -26,7 +26,7 @@ networkDependencyTreeInsightComponentStyles.replaceSync(networkDependencyTreeIns
 
 export class NetworkDependencyTree extends BaseInsightComponent<NetworkDependencyTreeInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-long-critical-network-tree`;
-  override internalName: string = 'long-critical-network-tree';
+  override internalName = 'long-critical-network-tree';
 
   override connectedCallback(): void {
     super.connectedCallback();
diff --git a/front_end/panels/timeline/components/insights/NodeLink.ts b/front_end/panels/timeline/components/insights/NodeLink.ts
index c4b4f6830d..31facadf4d 100644
--- a/front_end/panels/timeline/components/insights/NodeLink.ts
+++ b/front_end/panels/timeline/components/insights/NodeLink.ts
@@ -67,7 +67,7 @@ export class NodeLink extends HTMLElement {
 
     // TODO: it'd be nice if we could specify what attributes to render,
     // ex for the Viewport insight: <meta content="..."> (instead of just <meta>)
-    return Common.Linkifier.Linkifier.linkify(node, this.#options);
+    return await Common.Linkifier.Linkifier.linkify(node, this.#options);
   }
 
   async #render(): Promise<void> {
diff --git a/front_end/panels/timeline/components/insights/RenderBlocking.ts b/front_end/panels/timeline/components/insights/RenderBlocking.ts
index 9224db6f50..b9a9fef957 100644
--- a/front_end/panels/timeline/components/insights/RenderBlocking.ts
+++ b/front_end/panels/timeline/components/insights/RenderBlocking.ts
@@ -20,7 +20,7 @@ const {html} = Lit;
 
 export class RenderBlocking extends BaseInsightComponent<RenderBlockingInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-render-blocking-requests`;
-  override internalName: string = 'render-blocking-requests';
+  override internalName = 'render-blocking-requests';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     if (!this.model) {
diff --git a/front_end/panels/timeline/components/insights/SlowCSSSelector.ts b/front_end/panels/timeline/components/insights/SlowCSSSelector.ts
index 8e23ae9200..01f3fea95a 100644
--- a/front_end/panels/timeline/components/insights/SlowCSSSelector.ts
+++ b/front_end/panels/timeline/components/insights/SlowCSSSelector.ts
@@ -24,7 +24,7 @@ const {html} = Lit;
 
 export class SlowCSSSelector extends BaseInsightComponent<SlowCSSSelectorInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-slow-css-selector`;
-  override internalName: string = 'slow-css-selector';
+  override internalName = 'slow-css-selector';
   #selectorLocations = new Map<string, Protocol.CSS.SourceRange[]>();
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
diff --git a/front_end/panels/timeline/components/insights/Table.ts b/front_end/panels/timeline/components/insights/Table.ts
index ab1fa1ee5d..43061401f0 100644
--- a/front_end/panels/timeline/components/insights/Table.ts
+++ b/front_end/panels/timeline/components/insights/Table.ts
@@ -60,7 +60,7 @@ export class Table extends HTMLElement {
   #state?: TableState;
   #headers?: string[];
   #rows?: TableDataRow[];
-  #interactive: boolean = false;
+  #interactive = false;
   #currentHoverIndex: number|null = null;
 
   set data(data: TableData) {
diff --git a/front_end/panels/timeline/components/insights/ThirdParties.ts b/front_end/panels/timeline/components/insights/ThirdParties.ts
index bdb15d784b..01fca74112 100644
--- a/front_end/panels/timeline/components/insights/ThirdParties.ts
+++ b/front_end/panels/timeline/components/insights/ThirdParties.ts
@@ -19,7 +19,7 @@ const {html} = Lit;
 
 export class ThirdParties extends BaseInsightComponent<ThirdPartiesInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-third-parties`;
-  override internalName: string = 'third-parties';
+  override internalName = 'third-parties';
 
   #overlaysForEntity = new Map<Trace.Extras.ThirdParties.Entity, Overlays.Overlays.TimelineOverlay[]>();
 
diff --git a/front_end/panels/timeline/components/insights/Viewport.ts b/front_end/panels/timeline/components/insights/Viewport.ts
index 6eb64bba69..38a73145d7 100644
--- a/front_end/panels/timeline/components/insights/Viewport.ts
+++ b/front_end/panels/timeline/components/insights/Viewport.ts
@@ -15,7 +15,7 @@ const {html} = Lit;
 
 export class Viewport extends BaseInsightComponent<ViewportInsightModel> {
   static override readonly litTagName = Lit.StaticHtml.literal`devtools-performance-viewport`;
-  override internalName: string = 'viewport';
+  override internalName = 'viewport';
 
   override createOverlays(): Overlays.Overlays.TimelineOverlay[] {
     // TODO(b/351757418): create overlay for synthetic input delay events
diff --git a/front_end/panels/timeline/overlays/components/EntriesLinkOverlay.ts b/front_end/panels/timeline/overlays/components/EntriesLinkOverlay.ts
index 2cbb8d9b2f..155db980ac 100644
--- a/front_end/panels/timeline/overlays/components/EntriesLinkOverlay.ts
+++ b/front_end/panels/timeline/overlays/components/EntriesLinkOverlay.ts
@@ -44,17 +44,17 @@ export class EntriesLinkOverlay extends HTMLElement {
   #entryToWrapper: HTMLElement|null = null;
   #entryFromConnector: SVGCircleElement|null = null;
   #entryToConnector: SVGCircleElement|null = null;
-  #entryFromVisible: boolean = true;
-  #entryToVisible: boolean = true;
+  #entryFromVisible = true;
+  #entryToVisible = true;
   #canvasRect: DOMRect|null = null;
 
   // These flags let us know if the entry we are drawing from/to are the
   // originals, or if they are the parent, which can happen if an entry is
   // collapsed. We care about this because if the entry is not the source, we
   // draw the border as dashed, not solid.
-  #fromEntryIsSource: boolean = true;
-  #toEntryIsSource: boolean = true;
-  #arrowHidden: boolean = false;
+  #fromEntryIsSource = true;
+  #toEntryIsSource = true;
+  #arrowHidden = false;
   #linkState: Trace.Types.File.EntriesLinkState;
 
   constructor(
diff --git a/front_end/panels/timeline/overlays/components/EntryLabelOverlay.ts b/front_end/panels/timeline/overlays/components/EntryLabelOverlay.ts
index 5fa2dd1aa0..74ea16ddd2 100644
--- a/front_end/panels/timeline/overlays/components/EntryLabelOverlay.ts
+++ b/front_end/panels/timeline/overlays/components/EntryLabelOverlay.ts
@@ -66,11 +66,11 @@ export class EntryLabelOverlay extends HTMLElement {
   // can fire, and that triggers a second removal. So we set this flag after
   // the first removal to avoid a duplicate event firing which is a no-op but
   // causes errors when we try to delete an already deleted annotation.
-  #isPendingRemoval: boolean = false;
+  #isPendingRemoval = false;
 
   // The label is set to editable when it is double clicked. If the user clicks away from the label box
   // element, the label is set to not editable until it double clicked.s
-  #isLabelEditable: boolean = true;
+  #isLabelEditable = true;
   #entryLabelVisibleHeight: number|null = null;
 
   #labelPartsWrapper: HTMLElement|null = null;
@@ -99,7 +99,7 @@ export class EntryLabelOverlay extends HTMLElement {
    * Otherwise, the entry label overlay object only gets repositioned.
    */
 
-  constructor(label: string, shouldDrawBelowEntry: boolean = false) {
+  constructor(label: string, shouldDrawBelowEntry = false) {
     super();
     this.#render();
     this.#shouldDrawBelowEntry = shouldDrawBelowEntry;
diff --git a/front_end/panels/timeline/overlays/components/TimeRangeOverlay.ts b/front_end/panels/timeline/overlays/components/TimeRangeOverlay.ts
index 80d3286820..8ab37e9748 100644
--- a/front_end/panels/timeline/overlays/components/TimeRangeOverlay.ts
+++ b/front_end/panels/timeline/overlays/components/TimeRangeOverlay.ts
@@ -47,7 +47,7 @@ export class TimeRangeOverlay extends HTMLElement {
 
   // The label is set to editable and in focus anytime the label is empty and when the label it is double clicked.
   // If the user clicks away from the selected range element and the label is not empty, the label is set to not editable until it is double clicked.
-  #isLabelEditable: boolean = true;
+  #isLabelEditable = true;
 
   #rangeContainer: HTMLElement|null = null;
   #labelBox: HTMLElement|null = null;
diff --git a/front_end/panels/timeline/utils/ImageCache.test.ts b/front_end/panels/timeline/utils/ImageCache.test.ts
index 649c94cbbe..c453e87c13 100644
--- a/front_end/panels/timeline/utils/ImageCache.test.ts
+++ b/front_end/panels/timeline/utils/ImageCache.test.ts
@@ -78,7 +78,7 @@ describe('ImageCache', () => {
     }, {once: true});
 
     assert.isNull(getOrQueue(syntheticScreenshot1));
-    return promise;
+    return await promise;
   });
 
   it('getOrQueue should return null (immediately and eventually) for an invalid image', async () => {
@@ -96,7 +96,7 @@ describe('ImageCache', () => {
 
       resolve(null);
     }, {once: true});
-    return promise;
+    return await promise;
   });
 
   it('preload should load all screenshots', async () => {
diff --git a/front_end/panels/web_audio/WebAudioModel.ts b/front_end/panels/web_audio/WebAudioModel.ts
index 01a885985d..97a41bb0c8 100644
--- a/front_end/panels/web_audio/WebAudioModel.ts
+++ b/front_end/panels/web_audio/WebAudioModel.ts
@@ -40,7 +40,7 @@ export class WebAudioModel extends SDK.SDKModel.SDKModel<EventTypes> implements
 
   override async resumeModel(): Promise<void> {
     if (!this.enabled) {
-      return Promise.resolve();
+      return await Promise.resolve();
     }
     await this.agent.invoke_enable();
   }
diff --git a/front_end/panels/webauthn/WebauthnPane.ts b/front_end/panels/webauthn/WebauthnPane.ts
index 386c32ed12..d1c240acee 100644
--- a/front_end/panels/webauthn/WebauthnPane.ts
+++ b/front_end/panels/webauthn/WebauthnPane.ts
@@ -768,7 +768,7 @@ export class WebauthnPaneImpl extends UI.Widget.VBox implements
       return;
     }
 
-    // @ts-ignore dataGrid node type is indeterminate.
+    // @ts-expect-error dataGrid node type is indeterminate.
     dataGrid.rootNode()
         .children.find((n: DataGrid.DataGrid.DataGridNode<DataGridNode>) => n.data.credentialId === credentialId)
         .remove();
diff --git a/front_end/panels/whats_new/ReleaseNoteView.ts b/front_end/panels/whats_new/ReleaseNoteView.ts
index 9f1917c854..cf88a712ef 100644
--- a/front_end/panels/whats_new/ReleaseNoteView.ts
+++ b/front_end/panels/whats_new/ReleaseNoteView.ts
@@ -116,7 +116,7 @@ export class ReleaseNoteView extends UI.Widget.VBox {
     const url = new URL('./resources/WNDT.md', import.meta.url);
     try {
       const response = await fetch(url.toString());
-      return response.text();
+      return await response.text();
     } catch {
       throw new Error(`Markdown file ${
           url.toString()} not found. Make sure it is correctly listed in the relevant BUILD.gn files.`);
diff --git a/front_end/panels/whats_new/WhatsNewImpl.ts b/front_end/panels/whats_new/WhatsNewImpl.ts
index aac948fc0f..a034097b3f 100644
--- a/front_end/panels/whats_new/WhatsNewImpl.ts
+++ b/front_end/panels/whats_new/WhatsNewImpl.ts
@@ -11,7 +11,7 @@ import {getReleaseNote} from './ReleaseNoteText.js';
 
 export const releaseVersionSeen = 'releaseNoteVersionSeen';
 
-export const releaseNoteViewId: string = 'release-note';
+export const releaseNoteViewId = 'release-note';
 
 let releaseNoteVersionSetting: Common.Settings.Setting<number>;
 
diff --git a/front_end/testing/DOMHelpers.ts b/front_end/testing/DOMHelpers.ts
index 09e6b33464..4207bfd90c 100644
--- a/front_end/testing/DOMHelpers.ts
+++ b/front_end/testing/DOMHelpers.ts
@@ -248,11 +248,11 @@ export function getEventPromise<T extends Event>(element: HTMLElement, eventName
 }
 
 export async function doubleRaf() {
-  return new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+  return await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
 }
 
 export async function raf() {
-  return new Promise(resolve => requestAnimationFrame(resolve));
+  return await new Promise(resolve => requestAnimationFrame(resolve));
 }
 
 /**
diff --git a/front_end/testing/MockConnection.ts b/front_end/testing/MockConnection.ts
index 1864531c40..a9d760a7e4 100644
--- a/front_end/testing/MockConnection.ts
+++ b/front_end/testing/MockConnection.ts
@@ -134,7 +134,7 @@ async function disable() {
     throw new Error('MockConnection still has pending listeners. All promises should be awaited.');
   }
   await deinitializeGlobalVars();
-  // @ts-ignore Setting back to undefined as a hard reset.
+  // @ts-expect-error Setting back to undefined as a hard reset.
   ProtocolClient.InspectorBackend.Connection.setFactory(undefined);
 }
 
diff --git a/front_end/testing/MockScopeChain.ts b/front_end/testing/MockScopeChain.ts
index c6788330d1..9b0ca68596 100644
--- a/front_end/testing/MockScopeChain.ts
+++ b/front_end/testing/MockScopeChain.ts
@@ -56,7 +56,7 @@ export class MockProtocolBackend {
   }
 
   dispatchDebuggerPause(
-      script: SDK.Script.Script, reason: Protocol.Debugger.PausedEventReason, functionName: string = '',
+      script: SDK.Script.Script, reason: Protocol.Debugger.PausedEventReason, functionName = '',
       scopeChain: Protocol.Debugger.Scope[] = []): void {
     const target = script.debuggerModel.target();
     if (reason === Protocol.Debugger.PausedEventReason.Instrumentation) {
diff --git a/front_end/testing/MutationHelpers.ts b/front_end/testing/MutationHelpers.ts
index d89736baa1..cb53eb7a42 100644
--- a/front_end/testing/MutationHelpers.ts
+++ b/front_end/testing/MutationHelpers.ts
@@ -240,7 +240,7 @@ export const withNoMutations = async<T extends Node>(element: T, fn: (shadowRoot
 };
 
 export const someMutations = async<T extends Node>(element: T) => {
-  return new Promise<void>(resolve => {
+  return await new Promise<void>(resolve => {
     const observer = new MutationObserver(() => {
       resolve();
       observer.disconnect();
diff --git a/front_end/testing/ResourceTreeHelpers.ts b/front_end/testing/ResourceTreeHelpers.ts
index 20666432bc..80eff6957d 100644
--- a/front_end/testing/ResourceTreeHelpers.ts
+++ b/front_end/testing/ResourceTreeHelpers.ts
@@ -55,7 +55,7 @@ export async function getInitializedResourceTreeModel(target: SDK.Target.Target)
   const resourceTreeModel = target.model(SDK.ResourceTreeModel.ResourceTreeModel)!;
   return resourceTreeModel.cachedResourcesLoaded() ?
       resourceTreeModel :
-      resourceTreeModel.once(SDK.ResourceTreeModel.Events.CachedResourcesLoaded);
+      await resourceTreeModel.once(SDK.ResourceTreeModel.Events.CachedResourcesLoaded);
 }
 
 function getEffectivePayload(
diff --git a/front_end/testing/TraceHelpers.ts b/front_end/testing/TraceHelpers.ts
index a8a1613589..ea9f90efda 100644
--- a/front_end/testing/TraceHelpers.ts
+++ b/front_end/testing/TraceHelpers.ts
@@ -200,8 +200,7 @@ export function prettyPrint(
     tree: Trace.Helpers.TreeHelpers.TraceEntryTree,
     predicate: (node: Trace.Helpers.TreeHelpers.TraceEntryNode, event: Trace.Types.Events.Event) => boolean = () =>
         true,
-    indentation: number = 2, delimiter: string = ' ', prefix: string = '-', newline: string = '\n',
-    out: string = ''): string {
+    indentation = 2, delimiter = ' ', prefix = '-', newline = '\n', out = ''): string {
   let skipped = false;
   return printNodes(tree.roots);
   function printNodes(nodes: Set<Trace.Helpers.TreeHelpers.TraceEntryNode>|
@@ -231,8 +230,7 @@ export function prettyPrint(
  * Builds a mock Complete.
  */
 export function makeCompleteEvent(
-    name: string, ts: number, dur: number, cat: string = '*', pid: number = 0,
-    tid: number = 0): Trace.Types.Events.Complete {
+    name: string, ts: number, dur: number, cat = '*', pid = 0, tid = 0): Trace.Types.Events.Complete {
   return {
     args: {},
     cat,
@@ -248,8 +246,8 @@ export function makeCompleteEvent(
 export function makeAsyncStartEvent(
     name: string,
     ts: number,
-    pid: number = 0,
-    tid: number = 0,
+    pid = 0,
+    tid = 0,
     ): Trace.Types.Events.Async {
   return {
     args: {},
@@ -264,8 +262,8 @@ export function makeAsyncStartEvent(
 export function makeAsyncEndEvent(
     name: string,
     ts: number,
-    pid: number = 0,
-    tid: number = 0,
+    pid = 0,
+    tid = 0,
     ): Trace.Types.Events.Async {
   return {
     args: {},
@@ -282,9 +280,9 @@ export function makeAsyncEndEvent(
  * Builds a mock flow phase event.
  */
 export function makeFlowPhaseEvent(
-    name: string, ts: number, cat: string = '*',
+    name: string, ts: number, cat = '*',
     ph: Trace.Types.Events.Phase.FLOW_START|Trace.Types.Events.Phase.FLOW_END|Trace.Types.Events.Phase.FLOW_STEP,
-    id: number = 0, pid: number = 0, tid: number = 0): Trace.Types.Events.FlowEvent {
+    id = 0, pid = 0, tid = 0): Trace.Types.Events.FlowEvent {
   return {
     args: {},
     cat,
@@ -302,7 +300,7 @@ export function makeFlowPhaseEvent(
  * Builds flow phase events for a list of events belonging to the same
  * flow. `events` must be ordered.
  */
-export function makeFlowEvents(events: Trace.Types.Events.Event[], flowId: number = 0): Trace.Types.Events.FlowEvent[] {
+export function makeFlowEvents(events: Trace.Types.Events.Event[], flowId = 0): Trace.Types.Events.FlowEvent[] {
   const lastEvent = events.at(-1);
   const firstEvent = events.at(0);
   if (!lastEvent || !firstEvent) {
@@ -328,7 +326,7 @@ export function makeFlowEvents(events: Trace.Types.Events.Event[], flowId: numbe
  * Builds a mock Instant.
  */
 export function makeInstantEvent(
-    name: string, tsMicroseconds: number, cat: string = '', pid: number = 0, tid: number = 0,
+    name: string, tsMicroseconds: number, cat = '', pid = 0, tid = 0,
     s: Trace.Types.Events.Scope = Trace.Types.Events.Scope.THREAD): Trace.Types.Events.Instant {
   return {
     args: {},
@@ -345,8 +343,7 @@ export function makeInstantEvent(
 /**
  * Builds a mock Begin.
  */
-export function makeBeginEvent(
-    name: string, ts: number, cat: string = '*', pid: number = 0, tid: number = 0): Trace.Types.Events.Begin {
+export function makeBeginEvent(name: string, ts: number, cat = '*', pid = 0, tid = 0): Trace.Types.Events.Begin {
   return {
     args: {},
     cat,
@@ -361,8 +358,7 @@ export function makeBeginEvent(
 /**
  * Builds a mock End.
  */
-export function makeEndEvent(
-    name: string, ts: number, cat: string = '*', pid: number = 0, tid: number = 0): Trace.Types.Events.End {
+export function makeEndEvent(name: string, ts: number, cat = '*', pid = 0, tid = 0): Trace.Types.Events.End {
   return {
     args: {},
     cat,
@@ -375,8 +371,8 @@ export function makeEndEvent(
 }
 
 export function makeProfileCall(
-    functionName: string, tsUs: number, durUs: number, pid: number = 0, tid: number = 0, nodeId: number = 0,
-    url: string = ''): Trace.Types.Events.SyntheticProfileCall {
+    functionName: string, tsUs: number, durUs: number, pid = 0, tid = 0, nodeId = 0,
+    url = ''): Trace.Types.Events.SyntheticProfileCall {
   return {
     cat: '',
     name: 'ProfileCall',
@@ -404,8 +400,8 @@ export const DevToolsTimelineCategory = 'disabled-by-default-devtools.timeline';
  * Mocks an object compatible with the return type of the
  * RendererHandler using only an array of ordered entries.
  */
-export function makeMockRendererHandlerData(entries: Trace.Types.Events.Event[], pid: number = 1, tid: number = 1):
-    Trace.Handlers.ModelHandlers.Renderer.RendererHandlerData {
+export function makeMockRendererHandlerData(
+    entries: Trace.Types.Events.Event[], pid = 1, tid = 1): Trace.Handlers.ModelHandlers.Renderer.RendererHandlerData {
   const {tree, entryToNode} = Trace.Helpers.TreeHelpers.treify(entries, {filter: {has: () => true}});
   const mockThread: Trace.Handlers.ModelHandlers.Renderer.RendererThread = {
     tree,
diff --git a/front_end/testing/TraceLoader.ts b/front_end/testing/TraceLoader.ts
index b148801927..0c7155e585 100644
--- a/front_end/testing/TraceLoader.ts
+++ b/front_end/testing/TraceLoader.ts
@@ -212,7 +212,7 @@ export class TraceLoader {
   }> {
     const events = 'traceEvents' in contents ? contents.traceEvents : contents;
     const metadata = 'metadata' in contents ? contents.metadata : {};
-    return new Promise((resolve, reject) => {
+    return await new Promise((resolve, reject) => {
       const model = Trace.TraceModel.Model.createWithAllHandlers(traceEngineConfig);
       model.addEventListener(Trace.TraceModel.ModelUpdateEvent.eventName, (event: Event) => {
         const {data} = event as Trace.TraceModel.ModelUpdateEvent;
diff --git a/front_end/testing/UISourceCodeHelpers.ts b/front_end/testing/UISourceCodeHelpers.ts
index ceacfe76f0..7eea15e42e 100644
--- a/front_end/testing/UISourceCodeHelpers.ts
+++ b/front_end/testing/UISourceCodeHelpers.ts
@@ -139,7 +139,7 @@ export function createFileSystemUISourceCode(options: {
   return {uiSourceCode, project};
 }
 
-export function setupMockedUISourceCode(url: string = 'https://example.com/') {
+export function setupMockedUISourceCode(url = 'https://example.com/') {
   const projectStub = sinon.createStubInstance(Bindings.ContentProviderBasedProject.ContentProviderBasedProject);
   const urlStringTagExample = urlString`${url}`;
   const contentTypeStub = sinon.createStubInstance(Common.ResourceType.ResourceType);
diff --git a/front_end/ui/components/chrome_link/ChromeLink.ts b/front_end/ui/components/chrome_link/ChromeLink.ts
index 68581db78a..7967393bc3 100644
--- a/front_end/ui/components/chrome_link/ChromeLink.ts
+++ b/front_end/ui/components/chrome_link/ChromeLink.ts
@@ -23,7 +23,7 @@ declare global {
 export class ChromeLink extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   readonly #boundRender = this.#render.bind(this);
-  #href: string = '';
+  #href = '';
 
   connectedCallback(): void {
     void ComponentHelpers.ScheduledRender.scheduleRender(this, this.#boundRender);
diff --git a/front_end/ui/components/docs/tree_outline/lazy-children.ts b/front_end/ui/components/docs/tree_outline/lazy-children.ts
index 36f0400869..8c1528d509 100644
--- a/front_end/ui/components/docs/tree_outline/lazy-children.ts
+++ b/front_end/ui/components/docs/tree_outline/lazy-children.ts
@@ -33,7 +33,7 @@ async function loadInSomeNodes(): Promise<Array<TreeOutline.TreeOutlineUtils.Tre
     },
   ];
 
-  return new Promise(resolve => {
+  return await new Promise(resolve => {
     setTimeout(() => resolve(europeanOffices), 250);
   });
 }
diff --git a/front_end/ui/components/icon_button/IconButton.ts b/front_end/ui/components/icon_button/IconButton.ts
index a0f2b3bd64..5ee9b2dc53 100644
--- a/front_end/ui/components/icon_button/IconButton.ts
+++ b/front_end/ui/components/icon_button/IconButton.ts
@@ -32,9 +32,9 @@ export class IconButton extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   #clickHandler: undefined|(() => void) = undefined;
   #groups: IconWithTextData[] = [];
-  #compact: boolean = false;
-  #leadingText: string = '';
-  #trailingText: string = '';
+  #compact = false;
+  #leadingText = '';
+  #trailingText = '';
   #accessibleName: string|undefined;
 
   set data(data: IconButtonData) {
diff --git a/front_end/ui/components/issue_counter/IssueCounter.ts b/front_end/ui/components/issue_counter/IssueCounter.ts
index c812163564..e8f70fb139 100644
--- a/front_end/ui/components/issue_counter/IssueCounter.ts
+++ b/front_end/ui/components/issue_counter/IssueCounter.ts
@@ -81,7 +81,7 @@ const listFormatter = (function defineFormatter() {
 })();
 
 export function getIssueCountsEnumeration(
-    issuesManager: IssuesManager.IssuesManager.IssuesManager, omitEmpty: boolean = true): string {
+    issuesManager: IssuesManager.IssuesManager.IssuesManager, omitEmpty = true): string {
   const counts: [number, number, number] = [
     issuesManager.numberOfIssues(IssuesManager.Issue.IssueKind.PAGE_ERROR),
     issuesManager.numberOfIssues(IssuesManager.Issue.IssueKind.BREAKING_CHANGE),
@@ -99,7 +99,7 @@ export class IssueCounter extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   #clickHandler: undefined|(() => void) = undefined;
   #tooltipCallback: undefined|(() => void) = undefined;
-  #leadingText: string = '';
+  #leadingText = '';
   #throttler: undefined|Common.Throttler.Throttler;
   #counts: [number, number, number] = [0, 0, 0];
   #displayMode: DisplayMode = DisplayMode.OMIT_EMPTY;
diff --git a/front_end/ui/components/markdown_view/MarkdownLink.ts b/front_end/ui/components/markdown_view/MarkdownLink.ts
index 3143b473be..ee4e283fd7 100644
--- a/front_end/ui/components/markdown_view/MarkdownLink.ts
+++ b/front_end/ui/components/markdown_view/MarkdownLink.ts
@@ -27,8 +27,8 @@ export interface MarkdownLinkData {
 export class MarkdownLink extends HTMLElement {
 
   readonly #shadow = this.attachShadow({mode: 'open'});
-  #linkText: string = '';
-  #linkUrl: string = '';
+  #linkText = '';
+  #linkUrl = '';
 
   connectedCallback(): void {
     this.#shadow.adoptedStyleSheets = [markdownLinkStyles];
diff --git a/front_end/ui/components/menus/SelectMenu.ts b/front_end/ui/components/menus/SelectMenu.ts
index 11e506bafc..85b3e2d1c9 100644
--- a/front_end/ui/components/menus/SelectMenu.ts
+++ b/front_end/ui/components/menus/SelectMenu.ts
@@ -89,7 +89,7 @@ export class SelectMenu extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
   readonly #renderBound = this.#render.bind(this);
   #button: SelectMenuButton|null = null;
-  #open: boolean = false;
+  #open = false;
   #props: SelectMenuData = {
     buttonTitle: '',
     position: Dialogs.Dialog.DialogVerticalPosition.BOTTOM,
diff --git a/front_end/ui/components/node_text/NodeText.ts b/front_end/ui/components/node_text/NodeText.ts
index 3ea514d2ee..b810c1ccc9 100644
--- a/front_end/ui/components/node_text/NodeText.ts
+++ b/front_end/ui/components/node_text/NodeText.ts
@@ -21,7 +21,7 @@ export interface NodeTextData {
 export class NodeText extends HTMLElement {
 
   readonly #shadow = this.attachShadow({mode: 'open'});
-  #nodeTitle: string = '';
+  #nodeTitle = '';
   #nodeId?: string = '';
   #nodeClasses?: string[] = [];
 
diff --git a/front_end/ui/components/panel_feedback/PreviewToggle.ts b/front_end/ui/components/panel_feedback/PreviewToggle.ts
index 6ebae9ee5b..670e00cc40 100644
--- a/front_end/ui/components/panel_feedback/PreviewToggle.ts
+++ b/front_end/ui/components/panel_feedback/PreviewToggle.ts
@@ -49,7 +49,7 @@ export class PreviewToggle extends HTMLElement {
   #helperText: string|null = null;
   #feedbackURL: string|null = null;
   #learnMoreURL: string|undefined;
-  #experiment: string = '';
+  #experiment = '';
   #onChangeCallback?: (checked: boolean) => void;
 
   connectedCallback(): void {
diff --git a/front_end/ui/components/render_coordinator/render_coordinator.test.ts b/front_end/ui/components/render_coordinator/render_coordinator.test.ts
index b9e64fae59..f47f69701f 100644
--- a/front_end/ui/components/render_coordinator/render_coordinator.test.ts
+++ b/front_end/ui/components/render_coordinator/render_coordinator.test.ts
@@ -128,7 +128,7 @@ describe('RenderCoordinator', () => {
                          }, timeout));
     };
 
-    void RenderCoordinator.write(async () => delayedSet(expected, 100));
+    void RenderCoordinator.write(async () => await delayedSet(expected, 100));
     await RenderCoordinator.done();
 
     assert.strictEqual(targetValue, expected);
diff --git a/front_end/ui/components/render_coordinator/render_coordinator.ts b/front_end/ui/components/render_coordinator/render_coordinator.ts
index 20bd5bd00d..629c420824 100644
--- a/front_end/ui/components/render_coordinator/render_coordinator.ts
+++ b/front_end/ui/components/render_coordinator/render_coordinator.ts
@@ -116,10 +116,10 @@ export async function read<T>(
     if (!callback) {
       throw new Error('Read called with label but no callback');
     }
-    return enqueueHandler(ACTION.READ, labelOrCallback, callback);
+    return await enqueueHandler(ACTION.READ, labelOrCallback, callback);
   }
 
-  return enqueueHandler(ACTION.READ, UNNAMED_READ, labelOrCallback);
+  return await enqueueHandler(ACTION.READ, UNNAMED_READ, labelOrCallback);
 }
 
 /**
@@ -136,10 +136,10 @@ export async function write<T>(
     if (!callback) {
       throw new Error('Write called with label but no callback');
     }
-    return enqueueHandler(ACTION.WRITE, labelOrCallback, callback);
+    return await enqueueHandler(ACTION.WRITE, labelOrCallback, callback);
   }
 
-  return enqueueHandler(ACTION.WRITE, UNNAMED_WRITE, labelOrCallback);
+  return await enqueueHandler(ACTION.WRITE, UNNAMED_WRITE, labelOrCallback);
 }
 
 export function takeLoggingRecords(): LoggingRecord[] {
@@ -164,10 +164,10 @@ export async function scroll<T>(
     if (!callback) {
       throw new Error('Scroll called with label but no callback');
     }
-    return enqueueHandler(ACTION.READ, labelOrCallback, callback);
+    return await enqueueHandler(ACTION.READ, labelOrCallback, callback);
   }
 
-  return enqueueHandler(ACTION.READ, UNNAMED_SCROLL, labelOrCallback);
+  return await enqueueHandler(ACTION.READ, UNNAMED_SCROLL, labelOrCallback);
 }
 
 function enqueueHandler<T>(action: ACTION, label: string, callback: CoordinatorCallback<T>): Promise<T> {
diff --git a/front_end/ui/components/report_view/ReportView.ts b/front_end/ui/components/report_view/ReportView.ts
index 0cd069b8bf..00e54a01b8 100644
--- a/front_end/ui/components/report_view/ReportView.ts
+++ b/front_end/ui/components/report_view/ReportView.ts
@@ -59,7 +59,7 @@ export interface ReportData {
 }
 export class Report extends HTMLElement {
   readonly #shadow = this.attachShadow({mode: 'open'});
-  #reportTitle: string = '';
+  #reportTitle = '';
 
   set data({reportTitle}: ReportData) {
     this.#reportTitle = reportTitle;
diff --git a/front_end/ui/components/request_link_icon/RequestLinkIcon.test.ts b/front_end/ui/components/request_link_icon/RequestLinkIcon.test.ts
index 5bd6a10168..57bf100726 100644
--- a/front_end/ui/components/request_link_icon/RequestLinkIcon.test.ts
+++ b/front_end/ui/components/request_link_icon/RequestLinkIcon.test.ts
@@ -261,7 +261,7 @@ describeWithEnvironment('RequestLinkIcon', () => {
     before(() => {
       UI.ViewManager.resetViewRegistration();
       UI.ViewManager.registerViewExtension({
-        // @ts-ignore
+        // @ts-expect-error
         location: 'mock-location',
         id: 'network',
         title: () => 'Network' as Platform.UIString.LocalizedString,
diff --git a/front_end/ui/components/request_link_icon/RequestLinkIcon.ts b/front_end/ui/components/request_link_icon/RequestLinkIcon.ts
index fed1624c14..af91c30325 100644
--- a/front_end/ui/components/request_link_icon/RequestLinkIcon.ts
+++ b/front_end/ui/components/request_link_icon/RequestLinkIcon.ts
@@ -70,7 +70,7 @@ export class RequestLinkIcon extends HTMLElement {
   #request?: SDK.NetworkRequest.NetworkRequest|null;
   #highlightHeader?: {section: NetworkForward.UIRequestLocation.UIHeaderSection, name: string};
   #requestResolver?: Logs.RequestResolver.RequestResolver;
-  #displayURL: boolean = false;
+  #displayURL = false;
   #urlToDisplay?: string;
   #networkTab?: NetworkForward.UIRequestLocation.UIRequestTabs;
   #affectedRequest?: {requestId?: Protocol.Network.RequestId, url?: string};
@@ -180,7 +180,7 @@ export class RequestLinkIcon extends HTMLElement {
   }
 
   async #render(): Promise<void> {
-    return RenderCoordinator.write(() => {
+    return await RenderCoordinator.write(() => {
       // By default we render just the URL for the request link. If we also know
       // the concrete network request, or at least its request ID, we surround
       // the URL with a button, that opens the request in the Network panel.
diff --git a/front_end/ui/components/text_editor/AutocompleteHistory.ts b/front_end/ui/components/text_editor/AutocompleteHistory.ts
index cce9f3d297..dbd5e4f34f 100644
--- a/front_end/ui/components/text_editor/AutocompleteHistory.ts
+++ b/front_end/ui/components/text_editor/AutocompleteHistory.ts
@@ -17,8 +17,8 @@ export class AutocompleteHistory {
   #data: string[] = [];
 
   /** 1-based entry in the history stack. */
-  #historyOffset: number = 1;
-  #uncommittedIsTop: boolean = false;
+  #historyOffset = 1;
+  #uncommittedIsTop = false;
 
   /**
    * Creates a new settings-backed history. The class assumes it has sole
diff --git a/front_end/ui/components/text_editor/TextEditor.test.ts b/front_end/ui/components/text_editor/TextEditor.test.ts
index d82fc03181..1041d5dc6d 100644
--- a/front_end/ui/components/text_editor/TextEditor.test.ts
+++ b/front_end/ui/components/text_editor/TextEditor.test.ts
@@ -142,7 +142,7 @@ describeWithEnvironment('TextEditor', () => {
         code: string,
         pos: number,
         type?: TextEditor.JavaScript.QueryType,
-        range: string = '',
+        range = '',
         related?: string,
         ): Promise<void> {
       const state = makeState(code, CodeMirror.javascript.javascriptLanguage);
diff --git a/front_end/ui/components/text_editor/TextEditor.ts b/front_end/ui/components/text_editor/TextEditor.ts
index 7a5cdb1a06..7214bada6d 100644
--- a/front_end/ui/components/text_editor/TextEditor.ts
+++ b/front_end/ui/components/text_editor/TextEditor.ts
@@ -182,7 +182,7 @@ export class TextEditor extends HTMLElement {
     }
   }
 
-  revealPosition(selection: CodeMirror.EditorSelection, highlight: boolean = true): void {
+  revealPosition(selection: CodeMirror.EditorSelection, highlight = true): void {
     const view = this.#activeEditor;
     if (!view) {
       return;
diff --git a/front_end/ui/components/text_editor/javascript.ts b/front_end/ui/components/text_editor/javascript.ts
index 209f1c34ea..620fac1508 100644
--- a/front_end/ui/components/text_editor/javascript.ts
+++ b/front_end/ui/components/text_editor/javascript.ts
@@ -18,7 +18,7 @@ export function completion(): CodeMirror.Extension {
 }
 
 export async function completeInContext(
-    textBefore: string, query: string, force: boolean = false): Promise<UI.SuggestBox.Suggestions> {
+    textBefore: string, query: string, force = false): Promise<UI.SuggestBox.Suggestions> {
   const state = CodeMirror.EditorState.create({
     doc: textBefore + query,
     selection: {anchor: textBefore.length},
@@ -330,13 +330,13 @@ async function maybeCompleteKeysFromMap(objectVariable: string): Promise<Complet
 async function completeProperties(
     expression: string,
     quoted?: string,
-    hasBracket: boolean = false,
+    hasBracket = false,
     ): Promise<CompletionSet> {
   const cache = PropertyCache.instance();
   if (!quoted) {
     const cached = cache.get(expression);
     if (cached) {
-      return cached;
+      return await cached;
     }
   }
   const context = getExecutionContext();
@@ -347,14 +347,14 @@ async function completeProperties(
   if (!quoted) {
     cache.set(expression, result);
   }
-  return result;
+  return await result;
 }
 
 async function completePropertiesInner(
     expression: string,
     context: SDK.RuntimeModel.ExecutionContext,
     quoted?: string,
-    hasBracket: boolean = false,
+    hasBracket = false,
     ): Promise<CompletionSet> {
   const result = new CompletionSet();
   if (!context) {
@@ -425,7 +425,7 @@ async function completeExpressionGlobal(): Promise<CompletionSet> {
   const cache = PropertyCache.instance();
   const cached = cache.get('');
   if (cached) {
-    return cached;
+    return await cached;
   }
 
   const context = getExecutionContext();
@@ -446,7 +446,7 @@ async function completeExpressionGlobal(): Promise<CompletionSet> {
     });
   });
   cache.set('', fetchNames);
-  return fetchNames;
+  return await fetchNames;
 }
 
 export async function isExpressionComplete(expression: string): Promise<boolean> {
@@ -528,9 +528,9 @@ async function getArgumentsForExpression(
     if (!first || callee.name !== 'MemberExpression') {
       return null;
     }
-    return evaluateExpression(context, doc.sliceString(first.from, first.to), 'argumentsHint');
+    return await evaluateExpression(context, doc.sliceString(first.from, first.to), 'argumentsHint');
   };
-  return getArgumentsForFunctionValue(result, objGetter, expression)
+  return await getArgumentsForFunctionValue(result, objGetter, expression)
       .finally(() => context.runtimeModel.releaseObjectGroup('argumentsHint'));
 }
 
diff --git a/front_end/ui/components/tree_outline/TreeOutline.ts b/front_end/ui/components/tree_outline/TreeOutline.ts
index c635dca7fd..e661dd29a7 100644
--- a/front_end/ui/components/tree_outline/TreeOutline.ts
+++ b/front_end/ui/components/tree_outline/TreeOutline.ts
@@ -187,7 +187,7 @@ export class TreeOutline<TreeNodeDataType> extends HTMLElement {
    * Takes a TreeNode, expands the outline to reveal it, and focuses it.
    */
   async expandToAndSelectTreeNode(targetTreeNode: TreeNode<TreeNodeDataType>): Promise<void> {
-    return this.expandToAndSelectTreeNodeId(targetTreeNode.id);
+    return await this.expandToAndSelectTreeNodeId(targetTreeNode.id);
   }
 
   /**
@@ -546,7 +546,7 @@ export class TreeOutline<TreeNodeDataType> extends HTMLElement {
     // to ensure we're not rendering any stale UI.
     if (this.#enqueuedRender) {
       this.#enqueuedRender = false;
-      return this.#render();
+      return await this.#render();
     }
   }
 }
diff --git a/front_end/ui/legacy/ContextMenu.ts b/front_end/ui/legacy/ContextMenu.ts
index 678697900a..89ee6a951c 100644
--- a/front_end/ui/legacy/ContextMenu.ts
+++ b/front_end/ui/legacy/ContextMenu.ts
@@ -410,7 +410,7 @@ export class SubMenu extends Item {
     }
   }
 
-  private static uniqueSectionName: number = 0;
+  private static uniqueSectionName = 0;
 }
 
 export interface ContextMenuOptions {
diff --git a/front_end/ui/legacy/Geometry.ts b/front_end/ui/legacy/Geometry.ts
index 1b0e3e7263..bd0210ef5e 100644
--- a/front_end/ui/legacy/Geometry.ts
+++ b/front_end/ui/legacy/Geometry.ts
@@ -29,7 +29,7 @@
  */
 import * as SDK from '../../core/sdk/sdk.js';
 
-const EPS: number = 1e-5;
+const EPS = 1e-5;
 
 export class Vector {
   x: number;
diff --git a/front_end/ui/legacy/GlassPane.ts b/front_end/ui/legacy/GlassPane.ts
index a68e73f6f0..c61f02b8ad 100644
--- a/front_end/ui/legacy/GlassPane.ts
+++ b/front_end/ui/legacy/GlassPane.ts
@@ -23,7 +23,7 @@ export class GlassPane {
   private anchorBehavior: AnchorBehavior;
   private sizeBehavior: SizeBehavior;
   private marginBehavior: MarginBehavior;
-  #ignoreLeftMargin: boolean = false;
+  #ignoreLeftMargin = false;
 
   constructor(jslog?: string) {
     this.widgetInternal = new Widget(true);
diff --git a/front_end/ui/legacy/InspectorView.ts b/front_end/ui/legacy/InspectorView.ts
index 904674f3b6..56dd2387f6 100644
--- a/front_end/ui/legacy/InspectorView.ts
+++ b/front_end/ui/legacy/InspectorView.ts
@@ -313,7 +313,7 @@ export class InspectorView extends VBox implements ViewLocationResolver {
     if (!view) {
       throw new Error(`Expected view for panel '${panelName}'`);
     }
-    return view.widget() as Promise<Panel>;
+    return await (view.widget() as Promise<Panel>);
   }
 
   onSuspendStateChanged(allTargetsSuspended: boolean): void {
diff --git a/front_end/ui/legacy/KeyboardShortcut.ts b/front_end/ui/legacy/KeyboardShortcut.ts
index 262c7e861b..2a0c38abc6 100644
--- a/front_end/ui/legacy/KeyboardShortcut.ts
+++ b/front_end/ui/legacy/KeyboardShortcut.ts
@@ -118,7 +118,7 @@ export class KeyboardShortcut {
     }
 
     // Use either a real or a synthetic keyCode (for events originating from extensions).
-    // @ts-ignore ExtensionServer.js installs '__keyCode' on some events.
+    // @ts-expect-error ExtensionServer.js installs '__keyCode' on some events.
     const keyCode = keyboardEvent.keyCode || keyboardEvent['__keyCode'];
     return KeyboardShortcut.makeKeyFromCodeAndModifiers(keyCode, modifiers);
   }
diff --git a/front_end/ui/legacy/ListWidget.ts b/front_end/ui/legacy/ListWidget.ts
index 57948cd870..3351d7adc9 100644
--- a/front_end/ui/legacy/ListWidget.ts
+++ b/front_end/ui/legacy/ListWidget.ts
@@ -62,7 +62,7 @@ export class ListWidget<T> extends VBox {
   private editElement: Element|null;
   private emptyPlaceholder: Element|null;
   private isTable: boolean;
-  constructor(delegate: Delegate<T>, delegatesFocus: boolean|undefined = true, isTable: boolean = false) {
+  constructor(delegate: Delegate<T>, delegatesFocus: boolean|undefined = true, isTable = false) {
     super(true, delegatesFocus);
     this.registerRequiredCSS(listWidgetStyles);
     this.delegate = delegate;
diff --git a/front_end/ui/legacy/Panel.ts b/front_end/ui/legacy/Panel.ts
index ef1844a3f3..b8d8456a2f 100644
--- a/front_end/ui/legacy/Panel.ts
+++ b/front_end/ui/legacy/Panel.ts
@@ -48,12 +48,12 @@ export class Panel extends VBox {
     this.element.classList.add(name);
     this.panelName = name;
 
-    // @ts-ignore: Legacy global. Requires rewriting tests to get rid of.
+    // @ts-expect-error: Legacy global. Requires rewriting tests to get rid of.
     // For testing.
     self.UI = self.UI || {};
-    // @ts-ignore
+    // @ts-expect-error
     self.UI.panels = self.UI.panels || {};
-    // @ts-ignore
+    // @ts-expect-error
     UI.panels[name] = this;
   }
 
diff --git a/front_end/ui/legacy/ShortcutRegistry.ts b/front_end/ui/legacy/ShortcutRegistry.ts
index b53bd5ce77..51b374a2ef 100644
--- a/front_end/ui/legacy/ShortcutRegistry.ts
+++ b/front_end/ui/legacy/ShortcutRegistry.ts
@@ -431,7 +431,7 @@ export class ShortcutTreeNode {
   private chordsInternal: Map<number, ShortcutTreeNode>;
   private readonly depth: number;
 
-  constructor(key: number, depth: number = 0) {
+  constructor(key: number, depth = 0) {
     this.keyInternal = key;
     this.actionsInternal = [];
     this.chordsInternal = new Map();
diff --git a/front_end/ui/legacy/SuggestBox.ts b/front_end/ui/legacy/SuggestBox.ts
index dcd58ccbdb..7df63509e0 100644
--- a/front_end/ui/legacy/SuggestBox.ts
+++ b/front_end/ui/legacy/SuggestBox.ts
@@ -134,7 +134,7 @@ export class SuggestBox implements ListDelegate<Suggestion> {
       return kMaxWidth;
     }
     let maxItem;
-    let maxLength: number = -Infinity;
+    let maxLength = -Infinity;
     for (let i = 0; i < items.length; i++) {
       const length = (items[i].title || items[i].text).length + (items[i].subtitle || '').length;
       if (length > maxLength) {
diff --git a/front_end/ui/legacy/Toolbar.ts b/front_end/ui/legacy/Toolbar.ts
index 4420c7994f..9e0c1131ef 100644
--- a/front_end/ui/legacy/Toolbar.ts
+++ b/front_end/ui/legacy/Toolbar.ts
@@ -85,7 +85,7 @@ const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
 export class Toolbar extends HTMLElement {
   #shadowRoot = this.attachShadow({mode: 'open'});
   private items: ToolbarItem[] = [];
-  enabled: boolean = true;
+  enabled = true;
   private compactLayout = false;
 
   constructor() {
@@ -492,7 +492,7 @@ export class ToolbarItem<T = any, E extends HTMLElement = HTMLElement> extends C
   }
 
   applyEnabledState(enabled: boolean): void {
-    // @ts-ignore: Ignoring in favor of an `instanceof` check for all the different
+    // @ts-expect-error: Ignoring in favor of an `instanceof` check for all the different
     //             kind of HTMLElement classes that have a disabled attribute.
     this.element.disabled = !enabled;
   }
@@ -531,7 +531,7 @@ export class ToolbarItemWithCompactLayout extends ToolbarItem<ToolbarItemWithCom
 }
 
 export class ToolbarText extends ToolbarItem<void, HTMLElement> {
-  constructor(text: string = '') {
+  constructor(text = '') {
     const element = document.createElement('div');
     element.classList.add('toolbar-text');
     super(element);
@@ -943,7 +943,7 @@ export class ToolbarMenuButton extends ToolbarCombobox {
   private readonly contextMenuHandler: (arg0: ContextMenu) => void;
   private readonly useSoftMenu: boolean;
   private triggerTimeoutId?: number;
-  #triggerDelay: number = 200;
+  #triggerDelay = 200;
 
   constructor(
       contextMenuHandler: (arg0: ContextMenu) => void, isIconDropdown?: boolean, useSoftMenu?: boolean,
diff --git a/front_end/ui/legacy/Treeoutline.ts b/front_end/ui/legacy/Treeoutline.ts
index a1405b928f..3e6623281c 100644
--- a/front_end/ui/legacy/Treeoutline.ts
+++ b/front_end/ui/legacy/Treeoutline.ts
@@ -457,7 +457,7 @@ export class TreeElement {
   expanded: boolean;
   selected: boolean;
   private expandable!: boolean;
-  #expandRecursively: boolean = true;
+  #expandRecursively = true;
   private collapsible: boolean;
   toggleOnClick: boolean;
   button: Buttons.Button.Button|null;
diff --git a/front_end/ui/legacy/UIUtils.test.ts b/front_end/ui/legacy/UIUtils.test.ts
index 430811d224..c4017c985d 100644
--- a/front_end/ui/legacy/UIUtils.test.ts
+++ b/front_end/ui/legacy/UIUtils.test.ts
@@ -54,7 +54,7 @@ describe('UIUtils', () => {
       const el = document.createElement('div');
       const callback = sinon.spy();
       const controller = new UI.UIUtils.LongClickController(el, callback);
-      // @ts-ignore
+      // @ts-expect-error
       const setTimeout = sinon.stub(window, 'setTimeout').callsFake(cb => cb());
 
       el.dispatchEvent(new PointerEvent('pointerdown'));
diff --git a/front_end/ui/legacy/UIUtils.ts b/front_end/ui/legacy/UIUtils.ts
index 04591091c0..8d0409a3dc 100644
--- a/front_end/ui/legacy/UIUtils.ts
+++ b/front_end/ui/legacy/UIUtils.ts
@@ -1707,7 +1707,7 @@ export abstract class Renderer {
       return null;
     }
     const renderer = await extension.loadRenderer();
-    return renderer.render(object, options);
+    return await renderer.render(object, options);
   }
 }
 
diff --git a/front_end/ui/legacy/View.test.ts b/front_end/ui/legacy/View.test.ts
index c1a025a715..4171d1983a 100644
--- a/front_end/ui/legacy/View.test.ts
+++ b/front_end/ui/legacy/View.test.ts
@@ -14,7 +14,7 @@ describe('View', () => {
     before(async () => {
       ['first', 'second', 'third', 'fourth'].forEach(title => {
         UI.ViewManager.registerViewExtension({
-          // @ts-ignore
+          // @ts-expect-error
           location: 'mock-location',
           id: title as Lowercase<string>,
           title: () => title as Platform.UIString.LocalizedString,
diff --git a/front_end/ui/legacy/components/cookie_table/CookiesTable.ts b/front_end/ui/legacy/components/cookie_table/CookiesTable.ts
index 9e848b2f01..aa0f0b967f 100644
--- a/front_end/ui/legacy/components/cookie_table/CookiesTable.ts
+++ b/front_end/ui/legacy/components/cookie_table/CookiesTable.ts
@@ -470,7 +470,7 @@ export class CookiesTable extends UI.Widget.VBox {
 
   private createCookieData(cookie: SDK.Cookie.Cookie): CookieData {
     // See https://tc39.es/ecma262/#sec-time-values-and-time-range
-    const maxTime: number = 8640000000000000;
+    const maxTime = 8640000000000000;
     const isRequest = cookie.type() === SDK.Cookie.Type.REQUEST;
     const data: CookieData = {name: cookie.name(), value: cookie.value()};
     for (const attribute
diff --git a/front_end/ui/legacy/components/data_grid/DataGrid.ts b/front_end/ui/legacy/components/data_grid/DataGrid.ts
index d240317aee..cede4c50b5 100644
--- a/front_end/ui/legacy/components/data_grid/DataGrid.ts
+++ b/front_end/ui/legacy/components/data_grid/DataGrid.ts
@@ -534,7 +534,7 @@ export class DataGridImpl<T> extends Common.ObjectWrapper.ObjectWrapper<EventTyp
     this.dataTableColumnGroup.createChild('col', 'corner');
   }
 
-  protected setVerticalPadding(top: number, bottom: number, isConstructorTime: boolean = false): void {
+  protected setVerticalPadding(top: number, bottom: number, isConstructorTime = false): void {
     const topPx = top + 'px';
     const bottomPx = (top || bottom) ? bottom + 'px' : 'auto';
     if (this.topFillerRow.style.height === topPx && this.bottomFillerRow.style.height === bottomPx) {
@@ -1722,7 +1722,7 @@ export class DataGridNode<T> {
   parent: DataGridNode<T>|null;
   previousSibling: DataGridNode<T>|null;
   nextSibling: DataGridNode<T>|null;
-  #disclosureToggleHitBoxWidth: number = 20;
+  #disclosureToggleHitBoxWidth = 20;
   selectable: boolean;
   isRoot: boolean;
   nodeAccessibleText: string;
diff --git a/front_end/ui/legacy/components/data_grid/DataGridElement.test.ts b/front_end/ui/legacy/components/data_grid/DataGridElement.test.ts
index d5fd5e5556..7a62aa0701 100644
--- a/front_end/ui/legacy/components/data_grid/DataGridElement.test.ts
+++ b/front_end/ui/legacy/components/data_grid/DataGridElement.test.ts
@@ -56,11 +56,11 @@ describeWithEnvironment('DataGrid', () => {
   }
 
   async function renderDataGridContent(template: Lit.TemplateResult): Promise<HTMLElement> {
-    return renderDataGrid(html`<devtools-data-grid striped name="Display Name">${template}</devtools-data-grid>`);
+    return await renderDataGrid(html`<devtools-data-grid striped name="Display Name">${template}</devtools-data-grid>`);
   }
 
   async function renderDataGridWithData(columns: Lit.TemplateResult, rows: Lit.TemplateResult): Promise<HTMLElement> {
-    return renderDataGridContent(html`<table>${columns}${rows}</table>`);
+    return await renderDataGridContent(html`<table>${columns}${rows}</table>`);
   }
 
   it('can be configured from template', async () => {
diff --git a/front_end/ui/legacy/components/data_grid/ViewportDataGrid.ts b/front_end/ui/legacy/components/data_grid/ViewportDataGrid.ts
index 1b85a53eb4..bf300e55cc 100644
--- a/front_end/ui/legacy/components/data_grid/ViewportDataGrid.ts
+++ b/front_end/ui/legacy/components/data_grid/ViewportDataGrid.ts
@@ -19,11 +19,11 @@ export class ViewportDataGrid<T> extends Common.ObjectWrapper.eventMixin<EventTy
    * If `true`, the datagrid will mostly keep the scroll at the bottom, so new items are visible.
    * If the data is sorted descending (eg Performance Call Tree, heap snapshot), keep the default of `false`.
    */
-  enableAutoScrollToBottom: boolean = false;
+  enableAutoScrollToBottom = false;
   /** When true, the datagrid will manipulate the scrollTop to focus on the bottom, mostly so new additions are visible.
    * Some actions will unset this, like revealing or expanding a particular node.
    * Only matters if enableAutoScrollToBottom is true. */
-  keepScrollingToBottom: boolean = false;
+  keepScrollingToBottom = false;
   private updateIsFromUser: boolean;
   private lastScrollTop: number;
   private firstVisibleIsStriped: boolean;
diff --git a/front_end/ui/legacy/components/inline_editor/CSSShadowEditor.ts b/front_end/ui/legacy/components/inline_editor/CSSShadowEditor.ts
index 4bb628155b..b75b2c1662 100644
--- a/front_end/ui/legacy/components/inline_editor/CSSShadowEditor.ts
+++ b/front_end/ui/legacy/components/inline_editor/CSSShadowEditor.ts
@@ -36,10 +36,10 @@ const UIStrings = {
 const str_ = i18n.i18n.registerUIStrings('ui/legacy/components/inline_editor/CSSShadowEditor.ts', UIStrings);
 const i18nString = i18n.i18n.getLocalizedString.bind(undefined, str_);
 
-const maxRange: number = 20;
-const defaultUnit: string = 'px';
-const sliderThumbRadius: number = 6;
-const canvasSize: number = 88;
+const maxRange = 20;
+const defaultUnit = 'px';
+const sliderThumbRadius = 6;
+const canvasSize = 88;
 
 export interface CSSShadowModel {
   setInset(inset: boolean): void;
diff --git a/front_end/ui/legacy/components/inline_editor/ColorMixSwatch.ts b/front_end/ui/legacy/components/inline_editor/ColorMixSwatch.ts
index c088cb2d88..e714065330 100644
--- a/front_end/ui/legacy/components/inline_editor/ColorMixSwatch.ts
+++ b/front_end/ui/legacy/components/inline_editor/ColorMixSwatch.ts
@@ -23,9 +23,9 @@ export interface EventTypes {
 
 export class ColorMixSwatch extends Common.ObjectWrapper.eventMixin<EventTypes, typeof HTMLElement>(HTMLElement) {
   private readonly shadow = this.attachShadow({mode: 'open'});
-  private colorMixText: string = '';     // color-mix(in srgb, hotpink, white)
-  private firstColorText: string = '';   // hotpink
-  private secondColorText: string = '';  // white
+  private colorMixText = '';     // color-mix(in srgb, hotpink, white)
+  private firstColorText = '';   // hotpink
+  private secondColorText = '';  // white
   #registerPopoverCallback: undefined|((swatch: ColorMixSwatch) => void);
 
   constructor() {
diff --git a/front_end/ui/legacy/components/inline_editor/ColorSwatch.ts b/front_end/ui/legacy/components/inline_editor/ColorSwatch.ts
index 7cf9e61f0d..a9c5e1fa4c 100644
--- a/front_end/ui/legacy/components/inline_editor/ColorSwatch.ts
+++ b/front_end/ui/legacy/components/inline_editor/ColorSwatch.ts
@@ -48,7 +48,7 @@ export class ColorSwatch extends HTMLElement {
   private readonly shadow = this.attachShadow({mode: 'open'});
   private tooltip: string = i18nString(UIStrings.shiftclickToChangeColorFormat);
   private color: Common.Color.Color|null = null;
-  private readonly: boolean = false;
+  private readonly = false;
 
   constructor(tooltip?: string) {
     super();
diff --git a/front_end/ui/legacy/components/object_ui/JavaScriptREPL.ts b/front_end/ui/legacy/components/object_ui/JavaScriptREPL.ts
index 9c9e30144f..6396b1bdba 100644
--- a/front_end/ui/legacy/components/object_ui/JavaScriptREPL.ts
+++ b/front_end/ui/legacy/components/object_ui/JavaScriptREPL.ts
@@ -47,7 +47,7 @@ export class JavaScriptREPL {
 
   static async evaluateAndBuildPreview(
       text: string, throwOnSideEffect: boolean, replMode: boolean, timeout?: number, allowErrors?: boolean,
-      objectGroup?: string, awaitPromise: boolean = false, silent: boolean = false): Promise<{
+      objectGroup?: string, awaitPromise = false, silent = false): Promise<{
     preview: DocumentFragment,
     result: SDK.RuntimeModel.EvaluationResult|null,
   }> {
@@ -113,4 +113,4 @@ export class JavaScriptREPL {
   }
 }
 
-const maxLengthForEvaluation: number = 2000;
+const maxLengthForEvaluation = 2000;
diff --git a/front_end/ui/legacy/components/object_ui/ObjectPropertiesSection.ts b/front_end/ui/legacy/components/object_ui/ObjectPropertiesSection.ts
index 2ad87de95b..c4c65b9469 100644
--- a/front_end/ui/legacy/components/object_ui/ObjectPropertiesSection.ts
+++ b/front_end/ui/legacy/components/object_ui/ObjectPropertiesSection.ts
@@ -673,7 +673,7 @@ export class RootElement extends UI.TreeOutline.TreeElement {
   override async onpopulate(): Promise<void> {
     const treeOutline = (this.treeOutline as ObjectPropertiesSection | null);
     const skipProto = treeOutline ? Boolean(treeOutline.skipProtoInternal) : false;
-    return ObjectPropertyTreeElement.populate(
+    return await ObjectPropertyTreeElement.populate(
         this, this.object, skipProto, false, this.linkifier, this.emptyPlaceholder, this.propertiesMode,
         this.extraProperties, this.targetObject);
   }
@@ -848,9 +848,6 @@ export class ObjectPropertyTreeElement extends UI.TreeOutline.TreeElement {
     function onInvokeGetterClick(event: Event): void {
       event.consume();
       if (object) {
-        // The definition of callFunction expects an unknown, and setting to `any` causes Closure to fail.
-        // However, leaving this as unknown also causes TypeScript to fail, so for now we leave this as unchecked.
-        // @ts-ignore  TODO(crbug.com/1011811): Fix after Closure is removed.
         void object.callFunction(invokeGetter, [{value: JSON.stringify(propertyPath)}]).then(callback);
       }
     }
@@ -859,7 +856,7 @@ export class ObjectPropertyTreeElement extends UI.TreeOutline.TreeElement {
       let result: Object = this;
       const properties = JSON.parse(arrayStr);
       for (let i = 0, n = properties.length; i < n; ++i) {
-        // @ts-ignore callFunction expects this to be a generic Object, so while this works we can't be more specific on types.
+        // @ts-expect-error callFunction expects this to be a generic Object, so while this works we can't be more specific on types.
         result = result[properties[i]];
       }
       return result;
@@ -1047,7 +1044,7 @@ export class ObjectPropertyTreeElement extends UI.TreeOutline.TreeElement {
           function invokeGetter(getter) {
             return Reflect.apply(getter, this, []);
           }`;
-        // @ts-ignore No way to teach TypeScript to preserve the Function-ness of `getter`.
+        // @ts-expect-error No way to teach TypeScript to preserve the Function-ness of `getter`.
         // Also passing a string instead of a Function to avoid coverage implementation messing with it.
         void object.callFunction(invokeGetter, [SDK.RemoteObject.RemoteObject.toCallArgument(getter)])
             .then(this.onInvokeGetterClick.bind(this));
@@ -1433,7 +1430,7 @@ export class ArrayGroupingTreeElement extends UI.TreeOutline.TreeElement {
       const ranges = (result.ranges);
       if (ranges.length === 1) {
         // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-        // @ts-ignore
+        // @ts-expect-error
         await ArrayGroupingTreeElement.populateAsFragment(treeNode, object, ranges[0][0], ranges[0][1], linkifier);
       } else {
         for (let i = 0; i < ranges.length; ++i) {
@@ -1442,7 +1439,7 @@ export class ArrayGroupingTreeElement extends UI.TreeOutline.TreeElement {
           const count = ranges[i][2];
           if (fromIndex === toIndex) {
             // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-            // @ts-ignore
+            // @ts-expect-error
             await ArrayGroupingTreeElement.populateAsFragment(treeNode, object, fromIndex, toIndex, linkifier);
           } else {
             treeNode.appendChild(new ArrayGroupingTreeElement(object, fromIndex, toIndex, count, linkifier));
@@ -1451,7 +1448,7 @@ export class ArrayGroupingTreeElement extends UI.TreeOutline.TreeElement {
       }
       if (topLevel) {
         // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-        // @ts-ignore
+        // @ts-expect-error
         await ArrayGroupingTreeElement.populateNonIndexProperties(treeNode, object, linkifier);
       }
     }
@@ -1532,7 +1529,7 @@ export class ArrayGroupingTreeElement extends UI.TreeOutline.TreeElement {
       return;
     }
     // TODO(crbug.com/1172300) Ignored during the jsdoc to ts migration)
-    // @ts-ignore
+    // @ts-expect-error
     await ArrayGroupingTreeElement.populateAsFragment(this, this.object, this.fromIndex, this.toIndex, this.linkifier);
   }
 
diff --git a/front_end/ui/legacy/components/perf_ui/BrickBreaker.ts b/front_end/ui/legacy/components/perf_ui/BrickBreaker.ts
index 214debc617..1cc1eae079 100644
--- a/front_end/ui/legacy/components/perf_ui/BrickBreaker.ts
+++ b/front_end/ui/legacy/components/perf_ui/BrickBreaker.ts
@@ -115,7 +115,7 @@ export class BrickBreaker extends HTMLElement {
   #helperCanvas: HTMLCanvasElement;
   #helperCanvasCtx: CanvasRenderingContext2D;
   #scorePanel: HTMLElement;
-  #trackTimelineOffset: number = 0;
+  #trackTimelineOffset = 0;
   #visibleEntries = new Set<number>();
   #brokenBricks = new Map<number, Brick>();
   #keyDownHandlerBound = this.#keyDownHandler.bind(this);
@@ -125,7 +125,7 @@ export class BrickBreaker extends HTMLElement {
   #mouseMoveHandlerBound = this.#mouseMoveHandler.bind(this);
   #boundingElement = WindowBounds.WindowBoundsService.WindowBoundsServiceImpl.instance().getDevToolsBoundingElement();
   // Value by which we moved the game up relative to the viewport
-  #gameViewportOffset: number = 0;
+  #gameViewportOffset = 0;
   #running = false;
   #initialDPR = devicePixelRatio;
   #ballX = 0;
diff --git a/front_end/ui/legacy/components/perf_ui/CanvasHelper.ts b/front_end/ui/legacy/components/perf_ui/CanvasHelper.ts
index 044b69c925..6c1755111e 100644
--- a/front_end/ui/legacy/components/perf_ui/CanvasHelper.ts
+++ b/front_end/ui/legacy/components/perf_ui/CanvasHelper.ts
@@ -36,7 +36,7 @@ export function drawExpansionArrow(context: CanvasRenderingContext2D, x: number,
 
 export function drawIcon(
     context: CanvasRenderingContext2D, x: number, y: number, width: number, pathData: string,
-    iconColor: string = '--sys-color-on-surface'): void {
+    iconColor = '--sys-color-on-surface'): void {
   const p = new Path2D(pathData);
 
   context.save();
diff --git a/front_end/ui/legacy/components/perf_ui/FlameChart.ts b/front_end/ui/legacy/components/perf_ui/FlameChart.ts
index 1d7568acdc..8a3b18f02b 100644
--- a/front_end/ui/legacy/components/perf_ui/FlameChart.ts
+++ b/front_end/ui/legacy/components/perf_ui/FlameChart.ts
@@ -319,13 +319,13 @@ export class FlameChart extends Common.ObjectWrapper.eventMixin<EventTypes, type
   /** When true, all undimmed entries are outlined. When an array, only those indices are outlined (if not dimmed). */
   private dimShouldOutlineUndimmedEntries: boolean|Uint8Array = false;
 
-  #tooltipPopoverYAdjustment: number = 0;
+  #tooltipPopoverYAdjustment = 0;
 
   #font: string;
   #groupTreeRoot?: GroupTreeNode|null;
   #searchResultEntryIndex: number|null = null;
-  #inTrackConfigEditMode: boolean = false;
-  #linkSelectionAnnotationIsInProgress: boolean = false;
+  #inTrackConfigEditMode = false;
+  #linkSelectionAnnotationIsInProgress = false;
 
   // Stored because we cache this value to save extra lookups and layoffs.
   #canvasBoundingClientRect: DOMRect|null = null;
@@ -2210,7 +2210,7 @@ export class FlameChart extends Common.ObjectWrapper.eventMixin<EventTypes, type
       return timelineData.entryLevels[index] >= startLevel && timelineData.entryLevels[index] < endLevel &&
           barWidth > 10;
     };
-    let wideEntryExists: boolean = false;
+    let wideEntryExists = false;
     for (const [{color, outline}, {indexes}] of drawBatches) {
       if (!wideEntryExists) {
         wideEntryExists = indexes.some(entryIndexIsInTrack);
@@ -2832,7 +2832,7 @@ export class FlameChart extends Common.ObjectWrapper.eventMixin<EventTypes, type
     context.save();
     context.beginPath();
     let lastMarkerLevel = -1;
-    let lastMarkerX: number = -Infinity;
+    let lastMarkerX = -Infinity;
     // Markers are sorted top to bottom, right to left.
     for (let m = markerIndices.length - 1; m >= 0; --m) {
       const entryIndex = markerIndices[m];
@@ -3098,7 +3098,7 @@ export class FlameChart extends Common.ObjectWrapper.eventMixin<EventTypes, type
           Platform.ArrayUtilities.lowerBound(
               levelIndexes, timeWindowRight, (time, entryIndex) => time - entryStartTimes[entryIndex]) -
           1;
-      let lastDrawOffset: number = Infinity;
+      let lastDrawOffset = Infinity;
 
       for (let entryIndexOnLevel = rightIndexOnLevel; entryIndexOnLevel >= 0; --entryIndexOnLevel) {
         const entryIndex = levelIndexes[entryIndexOnLevel];
diff --git a/front_end/ui/legacy/components/perf_ui/OverviewGrid.ts b/front_end/ui/legacy/components/perf_ui/OverviewGrid.ts
index 048b181722..182a4b5329 100644
--- a/front_end/ui/legacy/components/perf_ui/OverviewGrid.ts
+++ b/front_end/ui/legacy/components/perf_ui/OverviewGrid.ts
@@ -178,8 +178,8 @@ export class Window extends Common.ObjectWrapper.ObjectWrapper<EventTypes> {
   private resizeEnabled?: boolean;
   private clickHandler?: ((arg0: Event) => boolean)|null;
   private resizerParentOffsetLeft?: number;
-  #breadcrumbsEnabled: boolean = false;
-  #mouseOverGridOverview: boolean = false;
+  #breadcrumbsEnabled = false;
+  #mouseOverGridOverview = false;
   constructor(parentElement: HTMLElement, dividersLabelBarElement?: Element, calculator?: Calculator) {
     super();
     this.parentElement = parentElement;
diff --git a/front_end/ui/legacy/components/perf_ui/TimelineOverviewCalculator.ts b/front_end/ui/legacy/components/perf_ui/TimelineOverviewCalculator.ts
index 6415842c22..24aebf9ed3 100644
--- a/front_end/ui/legacy/components/perf_ui/TimelineOverviewCalculator.ts
+++ b/front_end/ui/legacy/components/perf_ui/TimelineOverviewCalculator.ts
@@ -10,7 +10,7 @@ export class TimelineOverviewCalculator implements Calculator {
   #minimumBoundary: Trace.Types.Timing.Milli = Trace.Types.Timing.Milli(0);
   #maximumBoundary: Trace.Types.Timing.Milli = Trace.Types.Timing.Milli(100);
 
-  #displayWidth: number = 0;
+  #displayWidth = 0;
   private navStartTimes?: readonly Trace.Types.Events.NavigationStart[];
 
   /**
diff --git a/front_end/ui/legacy/components/quick_open/FilteredListWidget.ts b/front_end/ui/legacy/components/quick_open/FilteredListWidget.ts
index cd50fb2ce7..2f3f540e8f 100644
--- a/front_end/ui/legacy/components/quick_open/FilteredListWidget.ts
+++ b/front_end/ui/legacy/components/quick_open/FilteredListWidget.ts
@@ -176,7 +176,6 @@ export class FilteredListWidget extends Common.ObjectWrapper.eventMixin<EventTyp
     void this.dialog.once(UI.Dialog.Events.HIDDEN).then(() => {
       this.dispatchEventToListeners(Events.HIDDEN);
     });
-    // @ts-ignore
     this.dialog.show();
   }
 
diff --git a/front_end/ui/legacy/components/utils/ImagePreview.ts b/front_end/ui/legacy/components/utils/ImagePreview.ts
index ad0d62bb82..4069f3c91d 100644
--- a/front_end/ui/legacy/components/utils/ImagePreview.ts
+++ b/front_end/ui/legacy/components/utils/ImagePreview.ts
@@ -100,7 +100,7 @@ export class ImagePreview {
     const resourceSize = contentSize ? contentSize : Platform.StringUtilities.base64ToSize(content);
     const resourceSizeText = resourceSize > 0 ? i18n.ByteUtilities.bytesToString(resourceSize) : '';
 
-    return new Promise(resolve => {
+    return await new Promise(resolve => {
       const imageElement = document.createElement('img');
       imageElement.addEventListener('load', buildContent, false);
       imageElement.addEventListener('error', () => resolve(null), false);
diff --git a/front_end/ui/legacy/components/utils/Linkifier.ts b/front_end/ui/legacy/components/utils/Linkifier.ts
index 9df30976e1..524ecbaec0 100644
--- a/front_end/ui/legacy/components/utils/Linkifier.ts
+++ b/front_end/ui/legacy/components/utils/Linkifier.ts
@@ -595,7 +595,7 @@ export class Linkifier extends Common.ObjectWrapper.ObjectWrapper<EventTypes> im
       UI.Tooltip.Tooltip.install(link, title);
     }
     if (href) {
-      // @ts-ignore
+      // @ts-expect-error
       link.href = href;
     }
     link.setAttribute('jslog', `${VisualLogging.link(jslogContext).track({click: true})}`);
diff --git a/front_end/ui/legacy/components/utils/TargetDetachedDialog.ts b/front_end/ui/legacy/components/utils/TargetDetachedDialog.ts
index dd653c338c..4bff800eff 100644
--- a/front_end/ui/legacy/components/utils/TargetDetachedDialog.ts
+++ b/front_end/ui/legacy/components/utils/TargetDetachedDialog.ts
@@ -52,10 +52,6 @@ export class TargetDetachedDialog extends SDK.SDKModel.SDKModel<void> implements
         })
         .show(dialog.contentElement);
 
-    // UI.Dialog extends GlassPane and overrides the `show` method with a wider
-    // accepted type. However, TypeScript uses the supertype declaration to
-    // determine the full type, which requires a `!Document`.
-    // @ts-ignore
     dialog.show();
   }
 
diff --git a/front_end/ui/visual_logging/Debugging.ts b/front_end/ui/visual_logging/Debugging.ts
index f8eadc718b..658482136c 100644
--- a/front_end/ui/visual_logging/Debugging.ts
+++ b/front_end/ui/visual_logging/Debugging.ts
@@ -34,7 +34,7 @@ export function setVeDebuggingEnabled(enabled: boolean, inspect?: (query: string
   }
 }
 
-// @ts-ignore
+// @ts-expect-error
 globalThis.setVeDebuggingEnabled = setVeDebuggingEnabled;
 
 export function processForDebugging(loggable: Loggable): void {
@@ -686,7 +686,7 @@ export async function expectVeEvents(expectedEvents: TestLogEntry[]): Promise<vo
     }
   }, EVENT_EXPECTATION_TIMEOUT);
 
-  return promise.finally(() => {
+  return await promise.finally(() => {
     clearTimeout(timeout);
   });
 }
@@ -724,17 +724,17 @@ function getUnmatchedVeEvents(): string {
       .join('\n');
 }
 
-// @ts-ignore
+// @ts-expect-error
 globalThis.setVeDebugLoggingEnabled = setVeDebugLoggingEnabled;
-// @ts-ignore
+// @ts-expect-error
 globalThis.getUnmatchedVeEvents = getUnmatchedVeEvents;
-// @ts-ignore
+// @ts-expect-error
 globalThis.veDebugEventsLog = veDebugEventsLog;
-// @ts-ignore
+// @ts-expect-error
 globalThis.findVeDebugImpression = findVeDebugImpression;
-// @ts-ignore
+// @ts-expect-error
 globalThis.exportAdHocAnalysisLogForSql = exportAdHocAnalysisLogForSql;
-// @ts-ignore
+// @ts-expect-error
 globalThis.buildStateFlow = buildStateFlow;
-// @ts-ignore
+// @ts-expect-error
 globalThis.expectVeEvents = expectVeEvents;
diff --git a/front_end/ui/visual_logging/LoggingEvents.test.ts b/front_end/ui/visual_logging/LoggingEvents.test.ts
index add06f3ef9..481a6eb559 100644
--- a/front_end/ui/visual_logging/LoggingEvents.test.ts
+++ b/front_end/ui/visual_logging/LoggingEvents.test.ts
@@ -53,7 +53,7 @@ describe('LoggingEvents', () => {
         Host.InspectorFrontendHost.InspectorFrontendHostInstance,
         'recordClick',
     );
-    // @ts-ignore
+    // @ts-expect-error
     const event = new MouseEvent('click', {button: 0, sourceCapabilities: new InputDeviceCapabilities()});
     VisualLogging.LoggingEvents.logClick(throttler)(element, event);
     await assertThrottled(recordClick);
diff --git a/front_end/ui/visual_logging/visual_logging.ts b/front_end/ui/visual_logging/visual_logging.ts
index e3f51c68ff..a82ca36587 100644
--- a/front_end/ui/visual_logging/visual_logging.ts
+++ b/front_end/ui/visual_logging/visual_logging.ts
@@ -17,7 +17,7 @@ export const logClick = (loggable: Loggable, event: Event, options: {doubleClick
 
 export const logResize = (l: Loggable, s: DOMRect): void => LoggingEvents.logResize(l, s);
 export const logKeyDown = async(l: Loggable|null, e: Event, context?: string): Promise<void> =>
-    LoggingEvents.logKeyDown(LoggingDriver.keyboardLogThrottler)(l, e, context);
+    await LoggingEvents.logKeyDown(LoggingDriver.keyboardLogThrottler)(l, e, context);
 export {registerParentProvider, setMappedParent} from './LoggingState.js';
 
 export function registerLoggable(loggable: Loggable, config: string, parent: Loggable|null): void {
diff --git a/inspector_overlay/common.ts b/inspector_overlay/common.ts
index 42c154c5d1..f7d1d0c646 100644
--- a/inspector_overlay/common.ts
+++ b/inspector_overlay/common.ts
@@ -61,8 +61,8 @@ export class Overlay {
   protected scrollY = 0;
   protected style: CSSStyleSheet[];
   protected canvas?: HTMLCanvasElement;
-  protected canvasWidth: number = 0;
-  protected canvasHeight: number = 0;
+  protected canvasWidth = 0;
+  protected canvasHeight = 0;
   protected platform?: string;
   // eslint-disable-next-line @typescript-eslint/naming-convention
   private _window?: Window;
diff --git a/inspector_overlay/highlight_common.ts b/inspector_overlay/highlight_common.ts
index e84debc854..afd7fcb354 100644
--- a/inspector_overlay/highlight_common.ts
+++ b/inspector_overlay/highlight_common.ts
@@ -60,7 +60,7 @@ export const enum LinePattern {
 }
 
 export function drawPathWithLineStyle(
-    context: CanvasRenderingContext2D, path: Path2D, lineStyle?: LineStyle, lineWidth: number = 1) {
+    context: CanvasRenderingContext2D, path: Path2D, lineStyle?: LineStyle, lineWidth = 1) {
   if (lineStyle && lineStyle.color) {
     context.save();
     context.translate(0.5, 0.5);
@@ -171,7 +171,7 @@ export function applyMatrixToPoint(point: {x: number, y: number}, matrix: DOMMat
 const HATCH_LINE_LENGTH = 5;
 const HATCH_LINE_GAP = 3;
 let hatchLinePattern: CanvasPattern;
-let hatchLineColor: string = '';
+let hatchLineColor = '';
 
 /**
  * Draw line hatching at a 45 degree angle for a given
diff --git a/inspector_overlay/main.ts b/inspector_overlay/main.ts
index 8756da87ce..c0b1f307ff 100644
--- a/inspector_overlay/main.ts
+++ b/inspector_overlay/main.ts
@@ -2,33 +2,31 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import commonStyle from './common.css';
 import {adoptStyleSheet} from './common.js';
 import {gridStyle} from './highlight_grid_common.js';
 import {DistancesOverlay} from './tool_distances.js';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import highlightGridStyle from './tool_grid.css';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import highlightStyle from './tool_highlight.css';
 import {HighlightOverlay} from './tool_highlight.js';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import pausedStyle from './tool_paused.css';
 import {PausedOverlay, type PausedToolMessage} from './tool_paused.js';
 import {PersistentOverlay, type PersistentToolMessage} from './tool_persistent.js';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import screenshotStyle from './tool_screenshot.css';
 import {ScreenshotOverlay, type ScreenshotToolMessage} from './tool_screenshot.js';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import sourceOrderStyle from './tool_source_order.css';
 import {SourceOrderOverlay} from './tool_source_order.js';
 import {ViewportSizeOverlay} from './tool_viewport_size.js';
-// @ts-ignore Importing CSS is handled in Rollup.
+// @ts-expect-error Importing CSS is handled in Rollup.
 import wcoStyle from './tool_window_controls.css';
 import {WindowControlsOverlay} from './tool_window_controls.js';
 
-// @ts-ignore Importing CSS is handled in Rollup.
-
 declare global {
   interface Window {
     // eslint-disable-next-line @typescript-eslint/naming-convention
diff --git a/scripts/ai_assistance/auto-run.js b/scripts/ai_assistance/auto-run.js
index 281ab61a5d..dbf89e3873 100644
--- a/scripts/ai_assistance/auto-run.js
+++ b/scripts/ai_assistance/auto-run.js
@@ -13,7 +13,9 @@ const {parseComment} = require('./auto-run-helpers');
 const DEFAULT_FOLLOW_UP_QUERY = 'Fix the issue using JavaScript code execution.';
 
 const startTime = performance.now();
-const numberFormatter = new Intl.NumberFormat('en-EN', {maximumSignificantDigits: 3});
+const numberFormatter = new Intl.NumberFormat('en-EN', {
+  maximumSignificantDigits: 3,
+});
 const acquiredDevToolsTargets = new WeakMap();
 function formatElapsedTime() {
   return `${numberFormatter.format((performance.now() - startTime) / 1000)}s`;
@@ -102,7 +104,9 @@ class TraceDownloader {
     }, traceUrl);
     const foundFile = await TraceDownloader.ensureDownloadExists(fileName);
     if (!foundFile) {
-      console.error(`Could not find '${fileName}' in download location (${TraceDownloader.LOCATION}). Aborting.`);
+      console.error(
+          `Could not find '${fileName}' in download location (${TraceDownloader.LOCATION}). Aborting.`,
+      );
     }
     example.log(`Downloaded performance trace: ${fileName}`);
     return fileName;
@@ -122,7 +126,10 @@ class Logger {
   }
 
   #updateElapsedTime() {
-    this.#logs['elapsedTime'] = {index: 999, text: `\nElapsed time: ${formatElapsedTime()}`};
+    this.#logs['elapsedTime'] = {
+      index: 999,
+      text: `\nElapsed time: ${formatElapsedTime()}`,
+    };
     this.#flushLogs();
   }
 
@@ -208,7 +215,9 @@ class Example {
     const tracePath = path.join(TraceDownloader.LOCATION, fileName);
     await fileUploader.uploadFile(tracePath);
     this.log(`[Info]: imported ${fileName} to performance panel`);
-    const canvas = await devtoolsPage.waitForSelector(':scope >>> canvas.flame-chart-canvas');
+    const canvas = await devtoolsPage.waitForSelector(
+        ':scope >>> canvas.flame-chart-canvas',
+    );
     if (!canvas) {
       throw new Error('Could not find canvas.');
     }
@@ -246,10 +255,7 @@ class Example {
        * @return {Array<{comment: string, commentElement: Comment, targetElement: Element|null}>}
        */
       function collectComments(root) {
-        const walker = document.createTreeWalker(
-            root,
-            NodeFilter.SHOW_COMMENT,
-        );
+        const walker = document.createTreeWalker(root, NodeFilter.SHOW_COMMENT);
         const results = [];
         while (walker.nextNode()) {
           const comment = walker.currentNode;
@@ -288,10 +294,13 @@ class Example {
    * @returns {Promise<puppeteer.ElementHandle<HTMLElement>>} - the prompt from the annotation, if it exists, or undefined if one was not found.
    */
   async #lookForAnnotatedPerformanceEvent(devtoolsPage) {
-    const elem = await devtoolsPage.$('devtools-entry-label-overlay >>> [aria-label="Entry label"]');
+    const elem = await devtoolsPage.$(
+        'devtools-entry-label-overlay >>> [aria-label="Entry label"]',
+    );
     if (!elem) {
       throw new Error(
-          'Could not find annotated event in the performance panel. Only traces that have one entry label annotation are supported.');
+          'Could not find annotated event in the performance panel. Only traces that have one entry label annotation are supported.',
+      );
     }
 
     const overlay = /** @type{puppeteer.ElementHandle<HTMLElement>} */ (elem);
@@ -315,7 +324,9 @@ class Example {
     }
 
     const commentStringsFromPage = await this.#getCommentStringsFromPage(page);
-    const comments = commentStringsFromPage.map(comment => parseComment(comment));
+    const comments = commentStringsFromPage.map(
+        comment => parseComment(comment),
+    );
     // Only get the first comment for now.
     const comment = comments[0];
     const queries = [comment.prompt];
@@ -354,7 +365,7 @@ class Example {
 
     const devtoolsTarget = await this.#browser.waitForTarget(target => {
       const isAcquiredBefore = acquiredDevToolsTargets.has(target);
-      return target.type() === 'other' && target.url().startsWith('devtools://') && !isAcquiredBefore;
+      return (target.type() === 'other' && target.url().startsWith('devtools://') && !isAcquiredBefore);
     });
     acquiredDevToolsTargets.set(devtoolsTarget, true);
 
@@ -371,7 +382,7 @@ class Example {
     // Strip comments to prevent LLM from seeing it.
     await page.evaluate(() => {
       // @ts-expect-error we don't type globalThis.__commentElements
-      for (const {commentElement} of (globalThis.__commentElements ?? [])) {
+      for (const {commentElement} of globalThis.__commentElements ?? []) {
         commentElement.remove();
       }
     });
@@ -399,7 +410,9 @@ class Example {
       this.log('[Info]: Locating console');
       await devtoolsPage.locator(':scope >>> #tab-console').click();
       await devtoolsPage.locator('aria/Console prompt').click();
-      await devtoolsPage.keyboard.type(`inspect(globalThis.__commentElements[${idx}].targetElement)`);
+      await devtoolsPage.keyboard.type(
+          `inspect(globalThis.__commentElements[${idx}].targetElement)`,
+      );
       await devtoolsPage.keyboard.press('Enter');
 
       // Once we are done with the console, go back to the elements tab.
@@ -412,7 +425,9 @@ class Example {
       // Clicking on the annotation will also have the side-effect of selecting the event
       await performanceAnnotation.click();
       // Wait until the event is selected (confirming via the HTML in the details drawer)
-      await devtoolsPage.waitForSelector(':scope >>> .timeline-details-chip-title');
+      await devtoolsPage.waitForSelector(
+          ':scope >>> .timeline-details-chip-title',
+      );
     }
 
     this.log('[Info]: Locating AI assistance tab');
@@ -434,7 +449,9 @@ class Example {
       this.#ready = true;
     } catch (err) {
       this.#ready = false;
-      this.error(`Preparation failed.\n${err instanceof Error ? logger.formatError(err) : err}`);
+      this.error(
+          `Preparation failed.\n${err instanceof Error ? logger.formatError(err) : err}`,
+      );
     }
   }
 
@@ -466,7 +483,7 @@ class Example {
     });
 
     await this.#devtoolsPage.evaluate(() => {
-      // @ts-ignore this is run in the DevTools page context where this function does exist.
+      // @ts-expect-error this is run in the DevTools page context where this function does exist.
       setDebugAiAssistanceEnabled(true);
     });
 
@@ -506,11 +523,15 @@ class Example {
 
       const done = this.#devtoolsPage.evaluate(() => {
         return /** @type {Promise<void>} */ (new Promise(resolve => {
-          window.addEventListener('aiassistancedone', () => {
-            resolve();
-          }, {
-            once: true,
-          });
+          window.addEventListener(
+              'aiassistancedone',
+              () => {
+                resolve();
+              },
+              {
+                once: true,
+              },
+          );
         }));
       });
 
@@ -531,17 +552,24 @@ class Example {
     };
 
     for (const query of this.#queries) {
-      this.log(`[Info]: Running the user prompt "${query}" (This step might take long time)`);
+      this.log(
+          `[Info]: Running the user prompt "${query}" (This step might take long time)`,
+      );
       const result = await prompt(query);
       results.push(...result);
     }
 
     await this.#page.close();
-    const elapsedTime = numberFormatter.format((performance.now() - executionStartTime) / 1000);
+    const elapsedTime = numberFormatter.format(
+        (performance.now() - executionStartTime) / 1000,
+    );
     this.log(`Finished (${elapsedTime}s)`);
 
     /** @type {import('./types').ExecutedExample} */
-    return {results, metadata: {exampleId: this.id(), explanation: this.#explanation}};
+    return {
+      results,
+      metadata: {exampleId: this.id(), explanation: this.#explanation},
+    };
   }
 
   /**
@@ -550,8 +578,10 @@ class Example {
   log(text) {
     const indexOfExample = userArgs.exampleUrls.indexOf(this.#url);
     logger.log(
-        this.#url, indexOfExample,
-        `\x1b[33m[${indexOfExample + 1}/${userArgs.exampleUrls.length}] ${this.id()}:\x1b[0m ${text}`);
+        this.#url,
+        indexOfExample,
+        `\x1b[33m[${indexOfExample + 1}/${userArgs.exampleUrls.length}] ${this.id()}:\x1b[0m ${text}`,
+    );
   }
 
   /**
@@ -560,8 +590,10 @@ class Example {
   error(text) {
     const indexOfExample = userArgs.exampleUrls.indexOf(this.#url);
     logger.log(
-        this.#url, indexOfExample,
-        `\x1b[33m[${indexOfExample + 1}/${userArgs.exampleUrls.length}] ${this.id()}:\x1b[0m \x1b[31m${text}\x1b[0m`);
+        this.#url,
+        indexOfExample,
+        `\x1b[33m[${indexOfExample + 1}/${userArgs.exampleUrls.length}] ${this.id()}:\x1b[0m \x1b[31m${text}\x1b[0m`,
+    );
   }
 }
 
@@ -582,15 +614,19 @@ async function runInParallel(examples) {
   const allExampleResults = [];
   /** @type {Array<import('./types').ExampleMetadata>} **/
   const metadata = [];
-  await Promise.all(examples.filter(example => example.isReady()).map(async example => {
-    try {
-      const {results, metadata: singleMetadata} = await example.execute();
-      allExampleResults.push(...results);
-      metadata.push(singleMetadata);
-    } catch (err) {
-      example.error(`There is an error, skipping it.\n${err instanceof Error ? logger.formatError(err) : err}`);
-    }
-  }));
+  await Promise.all(
+      examples.filter(example => example.isReady()).map(async example => {
+        try {
+          const {results, metadata: singleMetadata} = await example.execute();
+          allExampleResults.push(...results);
+          metadata.push(singleMetadata);
+        } catch (err) {
+          example.error(
+              `There is an error, skipping it.\n${err instanceof Error ? logger.formatError(err) : err}`,
+          );
+        }
+      }),
+  );
 
   return {allExampleResults, metadata};
 }
@@ -617,7 +653,9 @@ async function runSequentially(examples) {
       allExampleResults.push(...results);
       metadata.push(singleMetadata);
     } catch (err) {
-      example.error(`There is an error, skipping it.\n${err instanceof Error ? logger.formatError(err) : err}`);
+      example.error(
+          `There is an error, skipping it.\n${err instanceof Error ? logger.formatError(err) : err}`,
+      );
     }
   }
 
@@ -641,7 +679,8 @@ async function main() {
   // Close any non about:blank pages. There should be only one
   // about:blank page and DevTools should be closed manually for it.
   logger.head(
-      'Getting browser pages... (If stuck in here, please close all the tabs in the connected Chrome manually.)');
+      'Getting browser pages... (If stuck in here, please close all the tabs in the connected Chrome manually.)',
+  );
   try {
     for (const page of await browser.pages()) {
       if (page.url() === 'about:blank') {
@@ -650,11 +689,15 @@ async function main() {
       await page.close();
     }
   } catch (err) {
-    logger.head(`There was an error closing pages\n${err instanceof Error ? err.stack : err}`);
+    logger.head(
+        `There was an error closing pages\n${err instanceof Error ? err.stack : err}`,
+    );
   }
 
   logger.head('Preparing examples...');
-  const examples = userArgs.exampleUrls.map(exampleUrl => new Example(exampleUrl, browser));
+  const examples = userArgs.exampleUrls.map(
+      exampleUrl => new Example(exampleUrl, browser),
+  );
   /** @type {import('./types').IndividualPromptRequestResponse[]} */
   let allExampleResults = [];
   /** @type {import('./types').ExampleMetadata[]} */
@@ -682,12 +725,17 @@ async function main() {
   };
 
   const dateSuffix = new Date().toISOString().slice(0, 19);
-  const outputPath = path.resolve(OUTPUT_DIR, `${userArgs.label}-${dateSuffix}.json`);
+  const outputPath = path.resolve(
+      OUTPUT_DIR,
+      `${userArgs.label}-${dateSuffix}.json`,
+  );
   if (!fs.existsSync(OUTPUT_DIR)) {
     fs.mkdirSync(OUTPUT_DIR);
   }
   fs.writeFileSync(outputPath, JSON.stringify(output, null, 2));
-  console.info(`\n[Info]: Finished exporting results to ${outputPath}, it took ${formatElapsedTime()}`);
+  console.info(
+      `\n[Info]: Finished exporting results to ${outputPath}, it took ${formatElapsedTime()}`,
+  );
   logger.destroy();
 }
 
diff --git a/scripts/build/code_generator_frontend.py b/scripts/build/code_generator_frontend.py
index 4046c3af9e..bdddb7aa8a 100644
--- a/scripts/build/code_generator_frontend.py
+++ b/scripts/build/code_generator_frontend.py
@@ -198,7 +198,7 @@ class Templates:
  *  ): void,
  * }}
  */
-// @ts-ignore typedef
+// @ts-expect-error typedef
 export let InspectorBackendAPI;
 
 /**
diff --git a/scripts/protocol_typescript/protocol_dts_generator.ts b/scripts/protocol_typescript/protocol_dts_generator.ts
index 1989f4b69f..86efdb7715 100644
--- a/scripts/protocol_typescript/protocol_dts_generator.ts
+++ b/scripts/protocol_typescript/protocol_dts_generator.ts
@@ -158,7 +158,7 @@ const emitProperty = (interfaceName: string, prop: Protocol.PropertyType) => {
   emitLine(`${getPropertyDef(interfaceName, prop)};`);
 };
 
-const emitInterface = (interfaceName: string, props?: Protocol.PropertyType[], optionalExtendsClause: string = '') => {
+const emitInterface = (interfaceName: string, props?: Protocol.PropertyType[], optionalExtendsClause = '') => {
   emitOpenBlock(`export interface ${interfaceName}${optionalExtendsClause}`);
   props ? props.forEach(prop => emitProperty(interfaceName, prop)) : emitLine('[key: string]: string;');
   emitCloseBlock();
diff --git a/test/conductor/mocha-interface-helpers.ts b/test/conductor/mocha-interface-helpers.ts
index 5833c7fad5..e2857e5acb 100644
--- a/test/conductor/mocha-interface-helpers.ts
+++ b/test/conductor/mocha-interface-helpers.ts
@@ -95,7 +95,7 @@ export function makeInstrumentedTestFunction(fn: Mocha.AsyncFunc, label: string)
     // AbortSignal for the current test function.
     AsyncScope.abortSignal = abortController.signal;
     // Promisify the function in case it is sync.
-    const promise = (async () => fn.call(this))();
+    const promise = (async () => await fn.call(this))();
     const actualTimeout = this.timeout();
     // Disable test timeout.
     this.timeout(0);
@@ -131,6 +131,6 @@ export function makeInstrumentedTestFunction(fn: Mocha.AsyncFunc, label: string)
           clearTimeout(t);
           this.timeout(actualTimeout);
         });
-    return testPromise;
+    return await testPromise;
   };
 }
diff --git a/test/conductor/pool.ts b/test/conductor/pool.ts
index 39a20a8036..17a00274f1 100644
--- a/test/conductor/pool.ts
+++ b/test/conductor/pool.ts
@@ -72,7 +72,7 @@ export class FrontendTargetPool {
     // used to resolve the `pair` promise of the `takeTabPair` call.
     void this.addTabPairToPool();
 
-    return pair;
+    return await pair;
   }
 }
 
diff --git a/test/conductor/screenshot-error.ts b/test/conductor/screenshot-error.ts
index 39904ee2ab..f2ca49047e 100644
--- a/test/conductor/screenshot-error.ts
+++ b/test/conductor/screenshot-error.ts
@@ -28,13 +28,13 @@ export class ScreenshotError extends Error {
 
     // To show Diffs mocha Spec reporter expects some properties.
     // See node_modules/mocha/lib/reporters/base.js.
-    // @ts-ignore forwarding error properties for Mocha.
+    // @ts-expect-error forwarding error properties for Mocha.
     this.showDiff = cause?.showDiff;
-    // @ts-ignore forwarding error properties for Mocha.
+    // @ts-expect-error forwarding error properties for Mocha.
     this.actual = cause?.actual;
-    // @ts-ignore forwarding error properties for Mocha.
+    // @ts-expect-error forwarding error properties for Mocha.
     this.expected = cause?.expected;
-    // @ts-ignore forwarding error properties for Mocha.
+    // @ts-expect-error forwarding error properties for Mocha.
     this.operator = cause?.operator;
   }
 
diff --git a/test/e2e/ai_assistance/ai_assistance_test.ts b/test/e2e/ai_assistance/ai_assistance_test.ts
index 0232a9fe2d..06513c341f 100644
--- a/test/e2e/ai_assistance/ai_assistance_test.ts
+++ b/test/e2e/ai_assistance/ai_assistance_test.ts
@@ -67,7 +67,7 @@ describe('AI Assistance', function() {
     await frontend.bringToFront();
     await frontend.evaluate(messages => {
       let call = 0;
-      // @ts-ignore devtools context.
+      // @ts-expect-error devtools context.
       globalThis.InspectorFrontendHost.doAidaConversation = async (request, streamId, cb) => {
         const response = JSON.stringify([
           {
@@ -81,7 +81,7 @@ describe('AI Assistance', function() {
         let first = true;
         for (const chunk of response.split(',{')) {
           await new Promise(resolve => setTimeout(resolve, 0));
-          // @ts-ignore devtools context.
+          // @ts-expect-error devtools context.
           globalThis.InspectorFrontendAPI.streamWrite(streamId, first ? chunk : ',{' + chunk);
           first = false;
         }
@@ -128,7 +128,7 @@ describe('AI Assistance', function() {
       return 'setDebugAiAssistanceEnabled' in window;
     });
     await frontend.evaluate(() => {
-      // @ts-ignore
+      // @ts-expect-error
       setDebugAiAssistanceEnabled(true);
     });
   }
@@ -331,9 +331,9 @@ STOP`,
     const {target} = getBrowserAndPages();
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('div')).backgroundColor === 'rgb(0, 0, 255)' &&
-          // @ts-ignore page context.
+          // @ts-expect-error page context.
           window.getComputedStyle(document.querySelector('body')).backgroundColor === 'rgb(0, 128, 0)';
     });
   });
@@ -355,7 +355,7 @@ STOP`,
     const {target} = getBrowserAndPages();
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('div')).backgroundColor === 'rgb(0, 0, 255)';
     });
 
@@ -374,7 +374,7 @@ STOP`,
 
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('button')).backgroundColor === 'rgb(0, 128, 0)';
     });
   });
@@ -398,7 +398,7 @@ STOP`,
     const {target} = getBrowserAndPages();
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('login-element').shadowRoot.querySelector('button'))
                  .backgroundColor === 'rgb(0, 0, 255)';
     });
@@ -420,7 +420,7 @@ STOP`,
     await target.bringToFront();
     await target.waitForFunction(() => {
       const buttonStyles =
-          // @ts-ignore page context.
+          // @ts-expect-error page context.
           window.getComputedStyle(document.querySelector('login-element').shadowRoot.querySelector('button'));
       return buttonStyles.backgroundColor === 'rgb(0, 0, 255)' && buttonStyles.color === 'rgb(0, 128, 0)';
     });
@@ -472,7 +472,7 @@ STOP`,
     const {target} = getBrowserAndPages();
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('div')).backgroundColor === 'rgba(0, 0, 0, 0)';
     });
 
@@ -501,7 +501,7 @@ STOP`,
 
     await target.bringToFront();
     await target.waitForFunction(() => {
-      // @ts-ignore page context.
+      // @ts-expect-error page context.
       return window.getComputedStyle(document.querySelector('div')).backgroundColor === 'rgb(0, 128, 0)';
     });
   });
diff --git a/test/e2e/application/storage_test.ts b/test/e2e/application/storage_test.ts
index aecf22112c..fff47696ef 100644
--- a/test/e2e/application/storage_test.ts
+++ b/test/e2e/application/storage_test.ts
@@ -33,11 +33,11 @@ describe('The Application Tab', () => {
         for (let i = 0; i < 20000; i++) {
           array.push(i % 10);
         }
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => createDatabase(resolve, 'Database1'));
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => createObjectStore(resolve, 'Database1', 'Store1', 'id', true));
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => addIDBValue(resolve, 'Database1', 'Store1', {key: 1, value: array}, ''));
       });
 
@@ -62,11 +62,11 @@ describe('The Application Tab', () => {
         for (let i = 0; i < 20000; i++) {
           array.push(i % 10);
         }
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => createDatabase(resolve, 'Database1'));
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => createObjectStore(resolve, 'Database1', 'Store1', 'id', true));
-        // @ts-ignore
+        // @ts-expect-error
         await new Promise(resolve => addIDBValue(resolve, 'Database1', 'Store1', {key: 1, value: array}, ''));
       });
 
diff --git a/test/e2e/emulation/custom-devices_test.ts b/test/e2e/emulation/custom-devices_test.ts
index 15e365df7b..8784dbca32 100644
--- a/test/e2e/emulation/custom-devices_test.ts
+++ b/test/e2e/emulation/custom-devices_test.ts
@@ -40,7 +40,7 @@ async function targetTextContent(selector: string): Promise<string> {
   if (!handle) {
     assert.fail(`targetTextContent: could not find element for ${selector}`);
   }
-  return elementTextContent(handle);
+  return await elementTextContent(handle);
 }
 
 describe('Custom devices', () => {
diff --git a/test/e2e/helpers/application-helpers.ts b/test/e2e/helpers/application-helpers.ts
index 9bc9b0e8c4..80afd89890 100644
--- a/test/e2e/helpers/application-helpers.ts
+++ b/test/e2e/helpers/application-helpers.ts
@@ -201,17 +201,17 @@ export async function getDataGridData(selector: string, columns: string[]) {
 
 export async function getTrimmedTextContent(selector: string) {
   const elements = await $$(selector);
-  return Promise.all(elements.map(element => element.evaluate(e => {
+  return await Promise.all(elements.map(element => element.evaluate(e => {
     return (e.textContent || '').trim().replace(/[ \n]{2,}/gm, '');  // remove multiple consecutive whitespaces
   })));
 }
 
 export async function getFrameTreeTitles() {
   const treeTitles = await $$('[aria-label="Resources Section"] ~ ol .tree-element-title');
-  return Promise.all(treeTitles.map(node => node.evaluate(e => e.textContent)));
+  return await Promise.all(treeTitles.map(node => node.evaluate(e => e.textContent)));
 }
 
-export async function getStorageItemsData(columns: string[], leastExpected: number = 1) {
+export async function getStorageItemsData(columns: string[], leastExpected = 1) {
   const gridData = await waitForFunction(async () => {
     const values = await getDataGridData('.storage-view table', columns);
     if (values.length >= leastExpected) {
diff --git a/test/e2e/helpers/changes-helpers.ts b/test/e2e/helpers/changes-helpers.ts
index b1bd1e2506..9e19e57cfa 100644
--- a/test/e2e/helpers/changes-helpers.ts
+++ b/test/e2e/helpers/changes-helpers.ts
@@ -45,7 +45,7 @@ export async function getChangesList() {
   const root = await waitFor(PANEL_ROOT_SELECTOR);
   const items = await $$('.tree-element-title', root);
 
-  return Promise.all(items.map(node => {
+  return await Promise.all(items.map(node => {
     return node.evaluate(node => node.textContent as string);
   }));
 }
@@ -53,7 +53,7 @@ export async function getChangesList() {
 export async function waitForNewChanges(initialChanges: string[]) {
   let newChanges = [];
 
-  return waitForFunction(async () => {
+  return await waitForFunction(async () => {
     newChanges = await getChangesList();
     return newChanges.length !== initialChanges.length;
   });
diff --git a/test/e2e/helpers/console-helpers.ts b/test/e2e/helpers/console-helpers.ts
index a54b289ff0..76d2e7cebf 100644
--- a/test/e2e/helpers/console-helpers.ts
+++ b/test/e2e/helpers/console-helpers.ts
@@ -116,7 +116,7 @@ export async function getConsoleMessages(testName: string, withAnchor = false, c
   // Have the target load the page.
   await goToResource(`console/${testName}.html`);
 
-  return getCurrentConsoleMessages(withAnchor, Level.All, callback);
+  return await getCurrentConsoleMessages(withAnchor, Level.All, callback);
 }
 
 export async function getCurrentConsoleMessages(withAnchor = false, level = Level.All, callback?: () => Promise<void>) {
@@ -154,7 +154,7 @@ export async function getCurrentConsoleMessages(withAnchor = false, level = Leve
   }, selector);
 }
 
-export async function getLastConsoleMessages(offset: number = 0) {
+export async function getLastConsoleMessages(offset = 0) {
   return (await getCurrentConsoleMessages()).at(-1 - offset);
 }
 
@@ -392,19 +392,18 @@ export async function clickOnContextMenu(selectorForNode: string, jslogContext:
  * Creates a function that runs a command and checks the nth output from the
  * bottom (checks last message by default)
  */
-export function checkCommandResultFunction(offset: number = 0) {
+export function checkCommandResultFunction(offset = 0) {
   return async function(command: string, expected: string, message?: string) {
     await typeIntoConsoleAndWaitForResult(command);
     assert.strictEqual(await getLastConsoleMessages(offset), expected, message);
   };
 }
 
-export async function getLastConsoleStacktrace(offset: number = 0) {
+export async function getLastConsoleStacktrace(offset = 0) {
   return (await getStructuredConsoleMessages()).at(-1 - offset)?.stackPreview as string;
 }
 
-export async function checkCommandStacktrace(
-    command: string, expected: string, leastMessages: number = 1, offset: number = 0) {
+export async function checkCommandStacktrace(command: string, expected: string, leastMessages = 1, offset = 0) {
   await typeIntoConsoleAndWaitForResult(command, leastMessages);
   await unifyLogVM(await getLastConsoleStacktrace(offset), expected);
 }
diff --git a/test/e2e/helpers/coverage-helpers.ts b/test/e2e/helpers/coverage-helpers.ts
index 2dcf324fcf..4cbc80f3f1 100644
--- a/test/e2e/helpers/coverage-helpers.ts
+++ b/test/e2e/helpers/coverage-helpers.ts
@@ -37,9 +37,9 @@ export async function clearCoverageContent() {
 
 export async function getCoverageData(expectedCount: number) {
   const rows = await waitForMany('.data-grid-data-grid-node', expectedCount, await waitFor('.coverage-results'));
-  return Promise.all(rows.map(r => r.evaluate((r: Element) => ({
-                                                url: r.querySelector('.url-column')?.textContent,
-                                                total: r.querySelector('.size-column')?.textContent,
-                                                unused: r.querySelector('.unused-size-column span')?.textContent,
-                                              }))));
+  return await Promise.all(rows.map(r => r.evaluate((r: Element) => ({
+                                                      url: r.querySelector('.url-column')?.textContent,
+                                                      total: r.querySelector('.size-column')?.textContent,
+                                                      unused: r.querySelector('.unused-size-column span')?.textContent,
+                                                    }))));
 }
diff --git a/test/e2e/helpers/datagrid-helpers.ts b/test/e2e/helpers/datagrid-helpers.ts
index 31fcd53714..364f7e4f5f 100644
--- a/test/e2e/helpers/datagrid-helpers.ts
+++ b/test/e2e/helpers/datagrid-helpers.ts
@@ -9,7 +9,7 @@ import {$$, waitFor, waitForFunction} from '../../shared/helper.js';
 
 export async function getDataGridRows(
     expectedNumberOfRows: number, root?: ElementHandle<Node>,
-    matchExactNumberOfRows: boolean = true): Promise<Array<Array<ElementHandle<HTMLTableCellElement>>>> {
+    matchExactNumberOfRows = true): Promise<Array<Array<ElementHandle<HTMLTableCellElement>>>> {
   const dataGrid = !root ? await waitFor('devtools-data-grid') : root;
   const handlers = await (async () => {
     if (matchExactNumberOfRows) {
@@ -24,7 +24,7 @@ export async function getDataGridRows(
     });
   })();
 
-  return Promise.all(handlers.map(handler => $$<HTMLTableCellElement>('td[jslog]:not(.hidden)', handler)));
+  return await Promise.all(handlers.map(handler => $$<HTMLTableCellElement>('td[jslog]:not(.hidden)', handler)));
 }
 
 export async function getDataGrid(root?: ElementHandle) {
@@ -42,7 +42,7 @@ export async function getDataGrid(root?: ElementHandle) {
 
 export async function getInnerTextOfDataGridCells(
     dataGridElement: ElementHandle<Element>, expectedNumberOfRows: number,
-    matchExactNumberOfRows: boolean = true): Promise<string[][]> {
+    matchExactNumberOfRows = true): Promise<string[][]> {
   const gridRows = await getDataGridRows(expectedNumberOfRows, dataGridElement, matchExactNumberOfRows);
   const table: string[][] = [];
   for (const row of gridRows) {
diff --git a/test/e2e/helpers/elements-helpers.ts b/test/e2e/helpers/elements-helpers.ts
index 62c1b1dd60..95211e2b93 100644
--- a/test/e2e/helpers/elements-helpers.ts
+++ b/test/e2e/helpers/elements-helpers.ts
@@ -239,10 +239,10 @@ export const waitForChildrenOfSelectedElementNode = async () => {
 };
 
 export const waitForAndClickTreeElementWithPartialText = async (text: string) =>
-    waitForFunction(async () => clickTreeElementWithPartialText(text));
+    await waitForFunction(async () => await clickTreeElementWithPartialText(text));
 
 export const waitForElementWithPartialText = async (text: string) => {
-  return waitForFunction(async () => elementWithPartialText(text));
+  return await waitForFunction(async () => await elementWithPartialText(text));
 };
 
 const elementWithPartialText = async (text: string) => {
@@ -471,12 +471,12 @@ export const getComputedStylesForDomNode =
 
 export const waitForNumberOfComputedProperties = async (numberToWaitFor: number) => {
   const computedPane = await getComputedPanel();
-  return waitForFunction(
+  return await waitForFunction(
       async () => numberToWaitFor ===
           await computedPane.$$eval('pierce/' + COMPUTED_PROPERTY_SELECTOR, properties => properties.length));
 };
 
-export const getComputedPanel = async () => waitFor(COMPUTED_STYLES_PANEL_SELECTOR);
+export const getComputedPanel = async () => await waitFor(COMPUTED_STYLES_PANEL_SELECTOR);
 
 export const filterComputedProperties = async (filterString: string) => {
   const initialContent = await getContentOfComputedPane();
@@ -554,7 +554,7 @@ export const getComputedStyleProperties = async () => {
 
 export const getDisplayedCSSDeclarations = async () => {
   const cssDeclarations = await $$(CSS_DECLARATION_SELECTOR);
-  return Promise.all(cssDeclarations.map(async node => await node.evaluate(n => n.textContent?.trim())));
+  return await Promise.all(cssDeclarations.map(async node => await node.evaluate(n => n.textContent?.trim())));
 };
 
 export const getDisplayedStyleRulesCompact = async () => {
@@ -682,7 +682,7 @@ export const getHiddenFontEditorButtons = async () => {
 
 export const getStyleSectionSubtitles = async () => {
   const subtitles = await $$(SECTION_SUBTITLE_SELECTOR);
-  return Promise.all(subtitles.map(node => node.evaluate(n => n.textContent)));
+  return await Promise.all(subtitles.map(node => node.evaluate(n => n.textContent)));
 };
 
 export const getCSSPropertyInRule =
diff --git a/test/e2e/helpers/extension-helpers.ts b/test/e2e/helpers/extension-helpers.ts
index 26857763fc..8e1d35c037 100644
--- a/test/e2e/helpers/extension-helpers.ts
+++ b/test/e2e/helpers/extension-helpers.ts
@@ -43,7 +43,7 @@ export async function loadExtension(name: string, startPage?: string, allowFileA
   // Because the injected script is shared across calls for the target, we cannot run multiple instances concurrently.
   const load = loadExtensionPromise.then(() => doLoad(frontend, extensionInfo));
   loadExtensionPromise = load.catch(() => {});
-  return load;
+  return await load;
 
   async function doLoad(frontend: puppeteer.Page, extensionInfo: {startPage: string, name: string}) {
     const session = (frontend as unknown as CdpPage)._client();
diff --git a/test/e2e/helpers/issues-helpers.ts b/test/e2e/helpers/issues-helpers.ts
index 300e457e33..a814def0a7 100644
--- a/test/e2e/helpers/issues-helpers.ts
+++ b/test/e2e/helpers/issues-helpers.ts
@@ -103,7 +103,7 @@ export async function getIssueByTitle(issueMessage: string): Promise<puppeteer.E
   const issueMessageElement = await waitFor(ISSUE_TITLE);
   const selectedIssueMessage = await issueMessageElement.evaluate(node => node.textContent);
   assert.strictEqual(selectedIssueMessage, issueMessage);
-  return getIssueByTitleElement(issueMessageElement);
+  return await getIssueByTitleElement(issueMessageElement);
 }
 
 // Works also if there are multiple issues.
@@ -121,7 +121,7 @@ export async function getAndExpandSpecificIssueByTitle(issueMessage: string):
   });
   await clickElement(issueMessageElement);
   await waitFor('.message');
-  return getIssueByTitleElement(issueMessageElement);
+  return await getIssueByTitleElement(issueMessageElement);
 }
 
 export async function getIssueHeaderByTitle(issueMessage: string):
diff --git a/test/e2e/helpers/lighthouse-helpers.ts b/test/e2e/helpers/lighthouse-helpers.ts
index 344c548740..a7d8f8f4db 100644
--- a/test/e2e/helpers/lighthouse-helpers.ts
+++ b/test/e2e/helpers/lighthouse-helpers.ts
@@ -45,7 +45,7 @@ export async function navigateToLighthouseTab(path?: string): Promise<ElementHan
     await frontend.bringToFront();
   }
 
-  return waitFor('.lighthouse-start-view');
+  return await waitFor('.lighthouse-start-view');
 }
 
 // Instead of watching the worker or controller/panel internals, we wait for the Lighthouse renderer
diff --git a/test/e2e/helpers/media-helpers.ts b/test/e2e/helpers/media-helpers.ts
index 569589f04f..5c5ebdb50f 100644
--- a/test/e2e/helpers/media-helpers.ts
+++ b/test/e2e/helpers/media-helpers.ts
@@ -63,7 +63,7 @@ export async function getPlayerButtonText() {
 }
 
 export async function waitForPlayerButtonTexts(count: number) {
-  return waitForFunction(async () => {
+  return await waitForFunction(async () => {
     return await waitForMany('.player-entry-player-title', count);
   });
 }
diff --git a/test/e2e/helpers/memory-helpers.ts b/test/e2e/helpers/memory-helpers.ts
index 0d948cad4a..74e9303a57 100644
--- a/test/e2e/helpers/memory-helpers.ts
+++ b/test/e2e/helpers/memory-helpers.ts
@@ -66,7 +66,7 @@ export async function takeAllocationTimelineProfile({recordStacks}: {recordStack
   await waitFor('.heap-snapshot-sidebar-tree-item.selected');
 }
 
-export async function takeHeapSnapshot(name: string = 'Snapshot 1') {
+export async function takeHeapSnapshot(name = 'Snapshot 1') {
   await click(NEW_HEAP_SNAPSHOT_BUTTON);
   await waitForNone('.heap-snapshot-sidebar-tree-item.wait');
   await waitForFunction(async () => {
@@ -154,7 +154,7 @@ export async function waitForSearchResultNumber(results: number) {
   return await waitForFunction(findMatch);
 }
 
-export async function findSearchResult(searchResult: string, pollIntrerval: number = 500) {
+export async function findSearchResult(searchResult: string, pollIntrerval = 500) {
   const {frontend} = getBrowserAndPages();
   const match = await waitFor('#profile-views table.data');
   const matches = await waitFor(' .search-results-matches');
@@ -182,7 +182,7 @@ export async function findSearchResult(searchResult: string, pollIntrerval: numb
           setTimeout(resolve, pollIntrerval, false);
         }),
       ]);
-      return result;
+      return await result;
     });
   }
 }
@@ -344,7 +344,7 @@ export async function getSizesFromSelectedRow() {
   return await getSizesFromRow(row);
 }
 
-export async function getCategoryRow(text: string, wait: boolean = true) {
+export async function getCategoryRow(text: string, wait = true) {
   const selector = `//td[text()="${text}"]/ancestor::tr`;
   return await (wait ? waitFor(selector, undefined, undefined, 'xpath') : $(selector, undefined, 'xpath'));
 }
diff --git a/test/e2e/helpers/sensors-helpers.ts b/test/e2e/helpers/sensors-helpers.ts
index ee29acc126..c5881f9a6b 100644
--- a/test/e2e/helpers/sensors-helpers.ts
+++ b/test/e2e/helpers/sensors-helpers.ts
@@ -16,10 +16,10 @@ export async function getInputFieldValue(field: ElementHandle<Element>): Promise
 }
 
 export async function getOrientationInputs() {
-  return waitForMany('.orientation-axis-input-container input', 3);
+  return await waitForMany('.orientation-axis-input-container input', 3);
 }
 
 export async function getOrientationValues() {
-  return Promise.all(
+  return await Promise.all(
       (await getOrientationInputs()).map(i => i.evaluate(i => parseInt((i as HTMLInputElement).value, 10))));
 }
diff --git a/test/e2e/helpers/settings-helpers.ts b/test/e2e/helpers/settings-helpers.ts
index 8f33b2158b..a1d383ffb9 100644
--- a/test/e2e/helpers/settings-helpers.ts
+++ b/test/e2e/helpers/settings-helpers.ts
@@ -25,7 +25,7 @@ export const openPanelViaMoreTools = async (panelTitle: string) => {
   await waitForFunction(async () => {
     // Open the “More Tools” option.
     await hover('aria/More tools[role="menuitem"]');
-    return $(`${panelTitle}[role="menuitem"]`, undefined, 'aria');
+    return await $(`${panelTitle}[role="menuitem"]`, undefined, 'aria');
   });
 
   // Click the desired menu item
diff --git a/test/e2e/helpers/settings-shortcuts-helpers.ts b/test/e2e/helpers/settings-shortcuts-helpers.ts
index d31cbb8c17..1a1cbefd76 100644
--- a/test/e2e/helpers/settings-shortcuts-helpers.ts
+++ b/test/e2e/helpers/settings-shortcuts-helpers.ts
@@ -98,7 +98,7 @@ export const shortcutsForAction = async (shortcutText: string) => {
   const shortcutElements = await listItemElement.$$(SHORTCUT_DISPLAY_SELECTOR);
   const shortcutElementsTextContent =
       await Promise.all(shortcutElements.map(element => element.getProperty('textContent')));
-  return Promise.all(
+  return await Promise.all(
       shortcutElementsTextContent.map(async textContent => textContent ? await textContent.jsonValue() : []));
 };
 
@@ -108,7 +108,7 @@ export const shortcutInputValues = async () => {
     assert.fail('shortcut input not found');
   }
   const shortcutValues = await Promise.all(shortcutInputs.map(async input => input.getProperty('value')));
-  return Promise.all(shortcutValues.map(async value => value ? await value.jsonValue() : []));
+  return await Promise.all(shortcutValues.map(async value => value ? await value.jsonValue() : []));
 };
 
 export const clickAddShortcutLink = async () => {
diff --git a/test/e2e/helpers/sources-helpers.ts b/test/e2e/helpers/sources-helpers.ts
index c8b978fc04..b7c2a64be7 100644
--- a/test/e2e/helpers/sources-helpers.ts
+++ b/test/e2e/helpers/sources-helpers.ts
@@ -189,7 +189,7 @@ export async function openSourceCodeEditorForFile(sourceFile: string, testInput:
 export async function getSelectedSource(): Promise<string> {
   const sourceTabPane = await waitFor('#sources-panel-sources-view .tabbed-pane');
   const sourceTabs = await waitFor('.tabbed-pane-header-tab.selected', sourceTabPane);
-  return sourceTabs.evaluate(node => node.getAttribute('aria-label')) as Promise<string>;
+  return await (sourceTabs.evaluate(node => node.getAttribute('aria-label')) as Promise<string>);
 }
 
 export async function getBreakpointHitLocation() {
@@ -231,7 +231,7 @@ export async function getToolbarText() {
     return [];
   }
   const textNodes = await $$('.toolbar-text', toolbar);
-  return Promise.all(textNodes.map(node => node.evaluate(node => node.textContent, node)));
+  return await Promise.all(textNodes.map(node => node.evaluate(node => node.textContent, node)));
 }
 
 export async function addBreakpointForLine(frontend: puppeteer.Page, index: number|string) {
@@ -297,7 +297,7 @@ export async function enableInlineBreakpointForLine(line: number, index: number)
  * @param expectNoBreakpoint If we should wait for the line to not have any inline breakpoints after
  *                           the click instead of a disabled one.
  */
-export async function disableInlineBreakpointForLine(line: number, index: number, expectNoBreakpoint: boolean = false) {
+export async function disableInlineBreakpointForLine(line: number, index: number, expectNoBreakpoint = false) {
   const {frontend} = getBrowserAndPages();
   const decorationSelector = `pierce/.cm-content > :nth-child(${line}) > :nth-child(${index} of .cm-inlineBreakpoint)`;
   await click(decorationSelector);
diff --git a/test/e2e/helpers/visual-logging-helpers.ts b/test/e2e/helpers/visual-logging-helpers.ts
index e71d263414..67855b0d7e 100644
--- a/test/e2e/helpers/visual-logging-helpers.ts
+++ b/test/e2e/helpers/visual-logging-helpers.ts
@@ -146,7 +146,7 @@ export function veImpressionForDrawerToolbar(options?: {
 export async function dumpVeEvents(label: string) {
   const {frontend} = getBrowserAndPages();
   const events =
-      // @ts-ignore
+      // @ts-expect-error
       await frontend.evaluate(async () => (await globalThis.getUnmatchedVeEvents()) as unknown as string[]);
   // eslint-disable-next-line no-console
   console.log(label + '\n', events);
@@ -159,7 +159,7 @@ export async function expectVeEvents(expectedEvents: TestLogEntry[], root?: stri
   prependRoot(expectedEvents, root);
 
   const {frontend} = getBrowserAndPages();
-  // @ts-ignore
+  // @ts-expect-error
   await frontend.evaluate(async expectedEvents => await globalThis.expectVeEvents(expectedEvents), expectedEvents);
 }
 
diff --git a/test/e2e/host/user-metrics_test.ts b/test/e2e/host/user-metrics_test.ts
index bd071a1872..bc69a6753f 100644
--- a/test/e2e/host/user-metrics_test.ts
+++ b/test/e2e/host/user-metrics_test.ts
@@ -68,12 +68,12 @@ declare global {
 }
 
 function retrieveRecordedHistogramEvents(frontend: puppeteer.Page): Promise<EnumHistogramEvent[]> {
-  // @ts-ignore
+  // @ts-expect-error
   return frontend.evaluate(() => window.InspectorFrontendHost.recordedEnumeratedHistograms);
 }
 
 function retrieveRecordedPerformanceHistogramEvents(frontend: puppeteer.Page): Promise<PerformanceHistogramEvent[]> {
-  // @ts-ignore
+  // @ts-expect-error
   return frontend.evaluate(() => window.InspectorFrontendHost.recordedPerformanceHistograms);
 }
 
diff --git a/test/e2e/inline_editor/color-swatch_test.ts b/test/e2e/inline_editor/color-swatch_test.ts
index 7b16d64aec..3d9631c375 100644
--- a/test/e2e/inline_editor/color-swatch_test.ts
+++ b/test/e2e/inline_editor/color-swatch_test.ts
@@ -21,7 +21,7 @@ import {
   waitForElementsComputedSection,
 } from '../helpers/elements-helpers.js';
 
-async function goToTestPageAndSelectTestElement(path: string = 'inline_editor/default.html') {
+async function goToTestPageAndSelectTestElement(path = 'inline_editor/default.html') {
   await goToResource(path);
   await waitForContentOfSelectedElementsNode('<body>\u200B');
   await clickNthChildOfSelectedElementNode(1);
diff --git a/test/e2e/inline_editor/font-editor_test.ts b/test/e2e/inline_editor/font-editor_test.ts
index a11801b71e..ca7c14c374 100644
--- a/test/e2e/inline_editor/font-editor_test.ts
+++ b/test/e2e/inline_editor/font-editor_test.ts
@@ -14,7 +14,7 @@ import {
   waitForCSSPropertyValue,
 } from '../helpers/elements-helpers.js';
 
-async function goToTestPageAndSelectTestElement(path: string = 'inline_editor/fontEditor.html') {
+async function goToTestPageAndSelectTestElement(path = 'inline_editor/fontEditor.html') {
   await goToResource(path);
   await waitForContentOfSelectedElementsNode('<body>\u200B');
   await clickNthChildOfSelectedElementNode(1);
diff --git a/test/e2e/issues/bounce-tracking-issues_test.ts b/test/e2e/issues/bounce-tracking-issues_test.ts
index f699b9747a..a6ad1ba8bf 100644
--- a/test/e2e/issues/bounce-tracking-issues_test.ts
+++ b/test/e2e/issues/bounce-tracking-issues_test.ts
@@ -30,7 +30,7 @@ describe('Bounce Tracking issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
       const issue2 = {
         code: 'BounceTrackingIssue',
@@ -40,7 +40,7 @@ describe('Bounce Tracking issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue2);
     });
     await expandIssue();
diff --git a/test/e2e/issues/cookie-deprecation-metadata-issues_test.ts b/test/e2e/issues/cookie-deprecation-metadata-issues_test.ts
index ba22befc3f..67ca40c67c 100644
--- a/test/e2e/issues/cookie-deprecation-metadata-issues_test.ts
+++ b/test/e2e/issues/cookie-deprecation-metadata-issues_test.ts
@@ -33,7 +33,7 @@ describe('Cookie Deprecation Metadata issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
       const issue2 = {
         code: 'CookieDeprecationMetadataIssue',
@@ -46,7 +46,7 @@ describe('Cookie Deprecation Metadata issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue2);
     });
     await expandIssue();
diff --git a/test/e2e/issues/cors-issues_test.ts b/test/e2e/issues/cors-issues_test.ts
index 02ba02f1a6..69a9483f12 100644
--- a/test/e2e/issues/cors-issues_test.ts
+++ b/test/e2e/issues/cors-issues_test.ts
@@ -15,95 +15,93 @@ import {
 } from '../helpers/issues-helpers.js';
 
 describe('CORS issues', () => {
-  it(
-      'should display CORS violations with the correct affected resources', async () => {
-        await goToResource('issues/cors-issue.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          // @ts-ignore
-          await window.doCorsFetches(`https://devtools.oopif.test:${document.location.port}`);
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure CORS response header values are valid');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('requests', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '3 requests');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Preflight Request (if problematic)',
-            'Header',
-            'Problem',
-            'Invalid Value (if available)',
-          ],
-          [
-            /^devtools.oopif.test:.*/,
-            'blocked',
-            '',
-            'Access-Control-Allow-Origin',
-            'Missing Header',
-            '',
-          ],
-          [
-            /^devtools.oopif.test:.*/,
-            'blocked',
-            /^devtools.oopif.test:.*/,
-            'Access-Control-Allow-Origin',
-            'Missing Header',
-            '',
-          ],
-          [
-            /.*invalid-preflight.*/,
-            'blocked',
-            /.*invalid-preflight.*/,
-            'Access-Control-Allow-Origin',
-            'Missing Header',
-            '',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display CORS violations with the correct affected resources', async () => {
+    await goToResource('issues/cors-issue.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      // @ts-expect-error
+      await window.doCorsFetches(`https://devtools.oopif.test:${document.location.port}`);
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure CORS response header values are valid');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('requests', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '3 requests');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Preflight Request (if problematic)',
+        'Header',
+        'Problem',
+        'Invalid Value (if available)',
+      ],
+      [
+        /^devtools.oopif.test:.*/,
+        'blocked',
+        '',
+        'Access-Control-Allow-Origin',
+        'Missing Header',
+        '',
+      ],
+      [
+        /^devtools.oopif.test:.*/,
+        'blocked',
+        /^devtools.oopif.test:.*/,
+        'Access-Control-Allow-Origin',
+        'Missing Header',
+        '',
+      ],
+      [
+        /.*invalid-preflight.*/,
+        'blocked',
+        /.*invalid-preflight.*/,
+        'Access-Control-Allow-Origin',
+        'Missing Header',
+        '',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display credentialed+wildcard CORS issues with the correct affected resources', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            const url = new URL('./issues/origin-wildcard.rawresponse', document.location.toString())
-                            .toString()
-                            .replace('localhost', 'devtools.oopif.test');
-            await fetch(url, {credentials: 'include'});
-          } catch {
-          }
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement =
-            await getIssueByTitle('Ensure credentialed requests are not sent to CORS resources with origin wildcards');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Preflight Request (if problematic)',
-          ],
-          [
-            'origin-wildcard.rawresponse',
-            'blocked',
-            '',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display credentialed+wildcard CORS issues with the correct affected resources', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        const url = new URL('./issues/origin-wildcard.rawresponse', document.location.toString())
+                        .toString()
+                        .replace('localhost', 'devtools.oopif.test');
+        await fetch(url, {credentials: 'include'});
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement =
+        await getIssueByTitle('Ensure credentialed requests are not sent to CORS resources with origin wildcards');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Preflight Request (if problematic)',
+      ],
+      [
+        'origin-wildcard.rawresponse',
+        'blocked',
+        '',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
   it('should display invalid CORS preflight response codes with the correct affected resources', async () => {
     await goToResource('empty.html');
@@ -216,58 +214,57 @@ describe('CORS issues', () => {
     await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
   });
 
-  it(
-      'should display invalid CORS ACAC values with the correct affected resources', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          const url = new URL('./issues/acac-invalid.rawresponse', document.location.toString())
-                          .toString()
-                          .replace('localhost', 'devtools.oopif.test');
-          try {
-            await fetch(url, {
-              method: 'POST',
-              credentials: 'include',
-              headers: {'Content-Type': 'application/json'},
-              body: JSON.stringify({geeting: 'hello'}),
-            });
-          } catch {
-          }
-          try {
-            await fetch(url, {credentials: 'include'});
-          } catch {
-          }
+  it('should display invalid CORS ACAC values with the correct affected resources', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      const url = new URL('./issues/acac-invalid.rawresponse', document.location.toString())
+                      .toString()
+                      .replace('localhost', 'devtools.oopif.test');
+      try {
+        await fetch(url, {
+          method: 'POST',
+          credentials: 'include',
+          headers: {'Content-Type': 'application/json'},
+          body: JSON.stringify({geeting: 'hello'}),
         });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure CORS requests include credentials only when allowed');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('requests', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '2 requests');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Preflight Request (if problematic)',
-            'Access-Control-Allow-Credentials Header Value',
-          ],
-          [
-            'acac-invalid.rawresponse',
-            'blocked',
-            'acac-invalid.rawresponse',
-            'false',
-          ],
-          [
-            'acac-invalid.rawresponse',
-            'blocked',
-            '',
-            'false',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+      } catch {
+      }
+      try {
+        await fetch(url, {credentials: 'include'});
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure CORS requests include credentials only when allowed');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('requests', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '2 requests');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Preflight Request (if problematic)',
+        'Access-Control-Allow-Credentials Header Value',
+      ],
+      [
+        'acac-invalid.rawresponse',
+        'blocked',
+        'acac-invalid.rawresponse',
+        'false',
+      ],
+      [
+        'acac-invalid.rawresponse',
+        'blocked',
+        '',
+        'false',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
   it('should display CORS requests using disallowed methods with the correct affected resources', async () => {
     await goToResource('empty.html');
@@ -310,194 +307,188 @@ describe('CORS issues', () => {
     await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
   });
 
-  it(
-      'should display CORS requests using disallowed headers with the correct affected resources', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            // We can re-use `method-disallowed.rawresponse` for this test.
-            const url = new URL('./issues/method-disallowed.rawresponse', document.location.toString())
-                            .toString()
-                            .replace('localhost', 'devtools.oopif.test');
-            await fetch(url, {
-              headers: {'X-Foo': 'bar'},
-            });
-          } catch {
-          }
+  it('should display CORS requests using disallowed headers with the correct affected resources', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        // We can re-use `method-disallowed.rawresponse` for this test.
+        const url = new URL('./issues/method-disallowed.rawresponse', document.location.toString())
+                        .toString()
+                        .replace('localhost', 'devtools.oopif.test');
+        await fetch(url, {
+          headers: {'X-Foo': 'bar'},
         });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure CORS request includes only allowed headers');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure CORS request includes only allowed headers');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
 
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Preflight Request',
-            'Disallowed Request Header',
-          ],
-          [
-            'method-disallowed.rawresponse',
-            'blocked',
-            'method-disallowed.rawresponse',
-            'x-foo',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Preflight Request',
+        'Disallowed Request Header',
+      ],
+      [
+        'method-disallowed.rawresponse',
+        'blocked',
+        'method-disallowed.rawresponse',
+        'x-foo',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display CORS requests redirecting to credentialed URLs', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            const url = new URL('./issues/credentialed-redirect.rawresponse', document.location.toString())
-                            .toString()
-                            .replace('localhost', 'devtools.oopif.test');
-            await fetch(url);
-          } catch {
-          }
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement =
-            await getIssueByTitle('Ensure CORS requests are not redirected to URLs containing credentials');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-          ],
-          [
-            'credentialed-redirect.rawresponse',
-            'blocked',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display CORS requests redirecting to credentialed URLs', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        const url = new URL('./issues/credentialed-redirect.rawresponse', document.location.toString())
+                        .toString()
+                        .replace('localhost', 'devtools.oopif.test');
+        await fetch(url);
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement =
+        await getIssueByTitle('Ensure CORS requests are not redirected to URLs containing credentials');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+      ],
+      [
+        'credentialed-redirect.rawresponse',
+        'blocked',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display CORS issues that are disallowed by the mode', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            const url =
-                new URL('/', document.location.toString()).toString().replace('localhost', 'devtools.oopif.test');
-            await fetch(url, {mode: 'same-origin'});
-          } catch {
-          }
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement =
-            await getIssueByTitle('Ensure only same-origin resources are fetched with same-origin request mode');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Initiator Context',
-            'Source Location',
-          ],
-          [
-            /^devtools.oopif.test.*\//,
-            'blocked',
-            /^https:\/\/localhost.*/,
-            /.*:\d+/,
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display CORS issues that are disallowed by the mode', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        const url = new URL('/', document.location.toString()).toString().replace('localhost', 'devtools.oopif.test');
+        await fetch(url, {mode: 'same-origin'});
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement =
+        await getIssueByTitle('Ensure only same-origin resources are fetched with same-origin request mode');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Initiator Context',
+        'Source Location',
+      ],
+      [
+        /^devtools.oopif.test.*\//,
+        'blocked',
+        /^https:\/\/localhost.*/,
+        /.*:\d+/,
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display CORS issues that are unsupported by the scheme', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            const url = new URL('/', document.location.toString())
-                            .toString()
-                            .replace('https://localhost', 'webdav://devtools.oopif.test');
-            await fetch(url);
-          } catch {
-          }
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure CORS requests are made on supported schemes');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Initiator Context',
-            'Source Location',
-            'Unsupported Scheme',
-          ],
-          [
-            /^devtools.oopif.test.*\//,
-            'blocked',
-            /^https:\/\/localhost.*/,
-            /.*:\d+/,
-            'webdav',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display CORS issues that are unsupported by the scheme', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        const url = new URL('/', document.location.toString())
+                        .toString()
+                        .replace('https://localhost', 'webdav://devtools.oopif.test');
+        await fetch(url);
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure CORS requests are made on supported schemes');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Initiator Context',
+        'Source Location',
+        'Unsupported Scheme',
+      ],
+      [
+        /^devtools.oopif.test.*\//,
+        'blocked',
+        /^https:\/\/localhost.*/,
+        /.*:\d+/,
+        'webdav',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display CORS issues that are misconfiguring the redirect mode', async () => {
-        await goToResource('empty.html');
-        const {target} = getBrowserAndPages();
-        await target.evaluate(async () => {
-          try {
-            const url = new URL('/', document.location.toString())
-                            .toString()
-                            .replace('https://localhost', 'webdav://devtools.oopif.test');
-            await fetch(url, {mode: 'no-cors', redirect: 'manual'});
-          } catch {
-          }
-        });
-        await navigateToIssuesTab();
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure no-cors requests configure redirect mode follow');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
-        const text = await section.label.evaluate(el => el.textContent);
-        assert.strictEqual(text, '1 request');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Source Location',
-          ],
-          [
-            /^devtools.oopif.test.*\//,
-            'blocked',
-            /.*:\d+/,
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+  it('should display CORS issues that are misconfiguring the redirect mode', async () => {
+    await goToResource('empty.html');
+    const {target} = getBrowserAndPages();
+    await target.evaluate(async () => {
+      try {
+        const url = new URL('/', document.location.toString())
+                        .toString()
+                        .replace('https://localhost', 'webdav://devtools.oopif.test');
+        await fetch(url, {mode: 'no-cors', redirect: 'manual'});
+      } catch {
+      }
+    });
+    await navigateToIssuesTab();
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure no-cors requests configure redirect mode follow');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('request', issueElement, '.cors-issue-affected-resource-label');
+    const text = await section.label.evaluate(el => el.textContent);
+    assert.strictEqual(text, '1 request');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Source Location',
+      ],
+      [
+        /^devtools.oopif.test.*\//,
+        'blocked',
+        /.*:\d+/,
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 });
diff --git a/test/e2e/issues/cors-private-network-issues_test.ts b/test/e2e/issues/cors-private-network-issues_test.ts
index 984f8b01f6..2792c05d77 100644
--- a/test/e2e/issues/cors-private-network-issues_test.ts
+++ b/test/e2e/issues/cors-private-network-issues_test.ts
@@ -37,7 +37,7 @@ describe('Cors Private Network issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
       const issue2 = {
         code: 'CorsIssue',
@@ -55,7 +55,7 @@ describe('Cors Private Network issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue2);
     });
 
@@ -91,157 +91,155 @@ describe('Cors Private Network issue', () => {
     await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
   });
 
-  it(
-      'should display correct information for secure contexts', async () => {
-        await navigateToIssuesTab();
-        const {frontend} = getBrowserAndPages();
-        frontend.evaluate(() => {
-          const issue = {
-            code: 'CorsIssue',
-            details: {
-              corsIssueDetails: {
-                clientSecurityState: {
-                  initiatorIsSecureContext: true,
-                  initiatorIPAddressSpace: 'Public',
-                  privateNetworkRequestPolicy: 'WarnFromInsecureToMorePrivate',
-                },
-                corsErrorStatus: {corsError: 'InsecurePrivateNetwork', failedParameter: ''},
-                isWarning: true,
-                request: {requestId: 'request-1', url: 'http://localhost/'},
-                resourceIPAddressSpace: 'Local',
-              },
+  it('should display correct information for secure contexts', async () => {
+    await navigateToIssuesTab();
+    const {frontend} = getBrowserAndPages();
+    frontend.evaluate(() => {
+      const issue = {
+        code: 'CorsIssue',
+        details: {
+          corsIssueDetails: {
+            clientSecurityState: {
+              initiatorIsSecureContext: true,
+              initiatorIPAddressSpace: 'Public',
+              privateNetworkRequestPolicy: 'WarnFromInsecureToMorePrivate',
             },
-          };
-          // @ts-ignore
-          window.addIssueForTest(issue);
-          const issue2 = {
-            code: 'CorsIssue',
-            details: {
-              corsIssueDetails: {
-                clientSecurityState: {
-                  initiatorIsSecureContext: true,
-                  initiatorIPAddressSpace: 'Unknown',
-                  privateNetworkRequestPolicy: 'WarnFromInsecureToMorePrivate',
-                },
-                corsErrorStatus: {corsError: 'InsecurePrivateNetwork', failedParameter: ''},
-                isWarning: true,
-                request: {requestId: 'request-1', url: 'http://example.com/'},
-                resourceIPAddressSpace: 'Local',
-              },
+            corsErrorStatus: {corsError: 'InsecurePrivateNetwork', failedParameter: ''},
+            isWarning: true,
+            request: {requestId: 'request-1', url: 'http://localhost/'},
+            resourceIPAddressSpace: 'Local',
+          },
+        },
+      };
+      // @ts-expect-error
+      window.addIssueForTest(issue);
+      const issue2 = {
+        code: 'CorsIssue',
+        details: {
+          corsIssueDetails: {
+            clientSecurityState: {
+              initiatorIsSecureContext: true,
+              initiatorIPAddressSpace: 'Unknown',
+              privateNetworkRequestPolicy: 'WarnFromInsecureToMorePrivate',
             },
-          };
-          // @ts-ignore
-          window.addIssueForTest(issue2);
-        });
+            corsErrorStatus: {corsError: 'InsecurePrivateNetwork', failedParameter: ''},
+            isWarning: true,
+            request: {requestId: 'request-1', url: 'http://example.com/'},
+            resourceIPAddressSpace: 'Local',
+          },
+        },
+      };
+      // @ts-expect-error
+      window.addIssueForTest(issue2);
+    });
 
-        await expandIssue();
-        const issueElement = await getIssueByTitle('Ensure private network requests are made from secure contexts');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('2 requests', issueElement, '.cors-issue-affected-resource-label');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Resource Address',
-            'Initiator Address',
-            'Initiator Context',
-          ],
-          [
-            'localhost/',
-            'warning',
-            'Local',
-            'Public',
-            'secure',
-          ],
-          [
-            'example.com/',
-            'warning',
-            'Local',
-            'Unknown',
-            'secure',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+    await expandIssue();
+    const issueElement = await getIssueByTitle('Ensure private network requests are made from secure contexts');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('2 requests', issueElement, '.cors-issue-affected-resource-label');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Resource Address',
+        'Initiator Address',
+        'Initiator Context',
+      ],
+      [
+        'localhost/',
+        'warning',
+        'Local',
+        'Public',
+        'secure',
+      ],
+      [
+        'example.com/',
+        'warning',
+        'Local',
+        'Unknown',
+        'secure',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
-  it(
-      'should display correct information for preflight request errors', async () => {
-        await navigateToIssuesTab();
-        const {frontend} = getBrowserAndPages();
-        frontend.evaluate(() => {
-          const issue = {
-            code: 'CorsIssue',
-            details: {
-              corsIssueDetails: {
-                clientSecurityState: {
-                  initiatorIsSecureContext: true,
-                  initiatorIPAddressSpace: 'Public',
-                  privateNetworkRequestPolicy: 'PreflightBlock',
-                },
-                corsErrorStatus: {corsError: 'PreflightMissingAllowPrivateNetwork', failedParameter: ''},
-                isWarning: false,
-                request: {requestId: 'request-1', url: 'http://localhost/'},
-                resourceIPAddressSpace: 'Local',
-              },
+  it('should display correct information for preflight request errors', async () => {
+    await navigateToIssuesTab();
+    const {frontend} = getBrowserAndPages();
+    frontend.evaluate(() => {
+      const issue = {
+        code: 'CorsIssue',
+        details: {
+          corsIssueDetails: {
+            clientSecurityState: {
+              initiatorIsSecureContext: true,
+              initiatorIPAddressSpace: 'Public',
+              privateNetworkRequestPolicy: 'PreflightBlock',
             },
-          };
-          // @ts-ignore
-          window.addIssueForTest(issue);
-          const issue2 = {
-            code: 'CorsIssue',
-            details: {
-              corsIssueDetails: {
-                clientSecurityState: {
-                  initiatorIsSecureContext: true,
-                  initiatorIPAddressSpace: 'Public',
-                  privateNetworkRequestPolicy: 'PreflightBlock',
-                },
-                corsErrorStatus: {corsError: 'PreflightInvalidAllowPrivateNetwork', failedParameter: 'shouldBeTrue'},
-                isWarning: false,
-                request: {requestId: 'request-1', url: 'http://example.com/'},
-                resourceIPAddressSpace: 'Local',
-              },
+            corsErrorStatus: {corsError: 'PreflightMissingAllowPrivateNetwork', failedParameter: ''},
+            isWarning: false,
+            request: {requestId: 'request-1', url: 'http://localhost/'},
+            resourceIPAddressSpace: 'Local',
+          },
+        },
+      };
+      // @ts-expect-error
+      window.addIssueForTest(issue);
+      const issue2 = {
+        code: 'CorsIssue',
+        details: {
+          corsIssueDetails: {
+            clientSecurityState: {
+              initiatorIsSecureContext: true,
+              initiatorIPAddressSpace: 'Public',
+              privateNetworkRequestPolicy: 'PreflightBlock',
             },
-          };
-          // @ts-ignore
-          window.addIssueForTest(issue2);
-        });
+            corsErrorStatus: {corsError: 'PreflightInvalidAllowPrivateNetwork', failedParameter: 'shouldBeTrue'},
+            isWarning: false,
+            request: {requestId: 'request-1', url: 'http://example.com/'},
+            resourceIPAddressSpace: 'Local',
+          },
+        },
+      };
+      // @ts-expect-error
+      window.addIssueForTest(issue2);
+    });
 
-        await expandIssue();
-        const issueElement =
-            await getIssueByTitle('Ensure private network requests are only made to resources that allow them');
-        assertNotNullOrUndefined(issueElement);
-        const section = await getResourcesElement('2 requests', issueElement, '.cors-issue-affected-resource-label');
-        await ensureResourceSectionIsExpanded(section);
-        const expectedTableRows = [
-          [
-            'Request',
-            'Status',
-            'Preflight Request',
-            'Invalid Value (if available)',
-            'Initiator Address',
-            'Initiator Context',
-          ],
-          [
-            'localhost/',
-            'blocked',
-            'localhost/',
-            '',
-            'Public',
-            'secure',
-          ],
-          [
-            'example.com/',
-            'blocked',
-            'example.com/',
-            'shouldBeTrue',
-            'Public',
-            'secure',
-          ],
-        ];
-        await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
-      });
+    await expandIssue();
+    const issueElement =
+        await getIssueByTitle('Ensure private network requests are only made to resources that allow them');
+    assertNotNullOrUndefined(issueElement);
+    const section = await getResourcesElement('2 requests', issueElement, '.cors-issue-affected-resource-label');
+    await ensureResourceSectionIsExpanded(section);
+    const expectedTableRows = [
+      [
+        'Request',
+        'Status',
+        'Preflight Request',
+        'Invalid Value (if available)',
+        'Initiator Address',
+        'Initiator Context',
+      ],
+      [
+        'localhost/',
+        'blocked',
+        'localhost/',
+        '',
+        'Public',
+        'secure',
+      ],
+      [
+        'example.com/',
+        'blocked',
+        'example.com/',
+        'shouldBeTrue',
+        'Public',
+        'secure',
+      ],
+    ];
+    await waitForTableFromResourceSectionContents(section.content, expectedTableRows);
+  });
 
   it('should display correct information for failed preflight requests', async () => {
     await navigateToIssuesTab();
@@ -263,7 +261,7 @@ describe('Cors Private Network issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/issues/deprecation-issues_test.ts b/test/e2e/issues/deprecation-issues_test.ts
index 11dcefda1d..091d95fef2 100644
--- a/test/e2e/issues/deprecation-issues_test.ts
+++ b/test/e2e/issues/deprecation-issues_test.ts
@@ -35,7 +35,7 @@ describe('Deprecation Issues', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/issues/expect-ct-issues_test.ts b/test/e2e/issues/expect-ct-issues_test.ts
index 9c27b22fcd..9fa42210f3 100644
--- a/test/e2e/issues/expect-ct-issues_test.ts
+++ b/test/e2e/issues/expect-ct-issues_test.ts
@@ -30,7 +30,7 @@ describe('Expect-CT Issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/issues/heavy-ad-issues_test.ts b/test/e2e/issues/heavy-ad-issues_test.ts
index eb7b98f807..cc7be71015 100644
--- a/test/e2e/issues/heavy-ad-issues_test.ts
+++ b/test/e2e/issues/heavy-ad-issues_test.ts
@@ -32,7 +32,7 @@ describe('Heavy Ad issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
       const issue2 = {
         code: 'HeavyAdIssue',
@@ -44,7 +44,7 @@ describe('Heavy Ad issue', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue2);
     });
     await expandIssue();
diff --git a/test/e2e/issues/hide-issues-menu_test.ts b/test/e2e/issues/hide-issues-menu_test.ts
index d66f3130a9..51092a25da 100644
--- a/test/e2e/issues/hide-issues-menu_test.ts
+++ b/test/e2e/issues/hide-issues-menu_test.ts
@@ -39,7 +39,7 @@ describe('Hide issues menu', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
     frontend.evaluate(() => {
@@ -56,7 +56,7 @@ describe('Hide issues menu', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/issues/privacy-sandbox-extensions-api_test.ts b/test/e2e/issues/privacy-sandbox-extensions-api_test.ts
index 1c1ddaa591..f7b8264bad 100644
--- a/test/e2e/issues/privacy-sandbox-extensions-api_test.ts
+++ b/test/e2e/issues/privacy-sandbox-extensions-api_test.ts
@@ -34,7 +34,7 @@ describe('Privacy Sandbox Extensions API', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/issues/quota-issues_test.ts b/test/e2e/issues/quota-issues_test.ts
index 1a06af59a0..d05451da05 100644
--- a/test/e2e/issues/quota-issues_test.ts
+++ b/test/e2e/issues/quota-issues_test.ts
@@ -34,7 +34,7 @@ describe('Quota Issues', () => {
           },
         },
       };
-      // @ts-ignore
+      // @ts-expect-error
       window.addIssueForTest(issue);
     });
 
diff --git a/test/e2e/network/network-request-view_test.ts b/test/e2e/network/network-request-view_test.ts
index 25eec3de90..b324fc8b13 100644
--- a/test/e2e/network/network-request-view_test.ts
+++ b/test/e2e/network/network-request-view_test.ts
@@ -223,7 +223,7 @@ describe('The Network Request view', () => {
         '[aria-label=EventStream][role=tab][aria-selected=true]',
         networkView,
     );
-    return waitFor('.event-source-messages-view');
+    return await waitFor('.event-source-messages-view');
   };
 
   interface EventSourceMessageRaw {
@@ -234,13 +234,13 @@ describe('The Network Request view', () => {
   }
 
   const waitForMessages = async (messagesView: puppeteer.ElementHandle<Element>, count: number) => {
-    return waitForFunction(async () => {
+    return await waitForFunction(async () => {
       const messages = await $$('.data-grid-data-grid-node', messagesView);
       if (messages.length !== count) {
         return undefined;
       }
 
-      return Promise.all(messages.map(message => {
+      return await Promise.all(messages.map(message => {
         return new Promise<EventSourceMessageRaw>(async resolve => {
           const [id, type, data] = await Promise.all([
             getTextContent('.id-column', message),
@@ -330,17 +330,17 @@ describe('The Network Request view', () => {
         root: networkView,
       });
       await waitFor('[aria-label=Messages][role=tab][aria-selected=true]', networkView);
-      return waitFor('.websocket-frame-view');
+      return await waitFor('.websocket-frame-view');
     };
 
     let messagesView = await navigateToWebsocketMessages();
     const waitForMessages = async (count: number) => {
-      return waitForFunction(async () => {
+      return await waitForFunction(async () => {
         const messages = await $$('.data-column.websocket-frame-view-td', messagesView);
         if (messages.length !== count) {
           return undefined;
         }
-        return Promise.all(messages.map(message => {
+        return await Promise.all(messages.map(message => {
           return message.evaluate(message => message.textContent || '');
         }));
       });
diff --git a/test/e2e/recorder/helpers.ts b/test/e2e/recorder/helpers.ts
index fa0b65742b..bb7f31ae86 100644
--- a/test/e2e/recorder/helpers.ts
+++ b/test/e2e/recorder/helpers.ts
@@ -239,7 +239,7 @@ export async function clickSelectButtonItem(itemLabel: string, root: string) {
 
 export async function setupRecorderWithScript(
     script: UserFlow,
-    path: string = 'recorder/recorder.html',
+    path = 'recorder/recorder.html',
     ): Promise<void> {
   await enableAndOpenRecorderPanel(path);
   await createAndStartRecording(script.title);
@@ -249,7 +249,7 @@ export async function setupRecorderWithScript(
 
 export async function setupRecorderWithScriptAndReplay(
     script: UserFlow,
-    path: string = 'recorder/recorder.html',
+    path = 'recorder/recorder.html',
     ): Promise<void> {
   await setupRecorderWithScript(script, path);
   const onceFinished = onReplayFinished();
diff --git a/test/e2e/rendering/Rendering_test.ts b/test/e2e/rendering/Rendering_test.ts
index 2308ccaa0d..a05c93a946 100644
--- a/test/e2e/rendering/Rendering_test.ts
+++ b/test/e2e/rendering/Rendering_test.ts
@@ -55,7 +55,6 @@ describe('Rendering pane', () => {
     });
 
     if (!hasSupport) {
-      // @ts-ignore
       this.skip();
     }
 
diff --git a/test/e2e/sensors/emulate-hardware-concurrency_test.ts b/test/e2e/sensors/emulate-hardware-concurrency_test.ts
index 0412cd81af..1e7d760c8b 100644
--- a/test/e2e/sensors/emulate-hardware-concurrency_test.ts
+++ b/test/e2e/sensors/emulate-hardware-concurrency_test.ts
@@ -11,7 +11,7 @@ import {openPanelViaMoreTools} from '../helpers/settings-helpers.js';
 
 async function waitForChangedConcurrency(lastConcurrency: number|undefined) {
   const {target} = getBrowserAndPages();
-  return waitForFunction(async () => {
+  return await waitForFunction(async () => {
     const newConcurrency = await target.evaluate('navigator.hardwareConcurrency') as number;
     if (newConcurrency !== lastConcurrency) {
       return newConcurrency;
diff --git a/test/shared/helper.ts b/test/shared/helper.ts
index 43397e5057..b1e5985a3d 100644
--- a/test/shared/helper.ts
+++ b/test/shared/helper.ts
@@ -80,7 +80,7 @@ async function performActionOnSelector(
       break;
     }
   }
-  return waitForFunction(async () => {
+  return await waitForFunction(async () => {
     const element = await waitFor(selector, options?.root, undefined, queryHandler);
     try {
       await action(element);
@@ -142,7 +142,7 @@ export const doubleClick =
     ...passedClickOptions,
     clickCount: 2,
   };
-  return click(selector, {
+  return await click(selector, {
     ...options,
     clickOptions: clickOptionsWithDoubleClick,
   });
@@ -223,7 +223,7 @@ export const $$ =
  * @param root The root of the search.
  */
 export const $textContent = async (textContent: string, root?: puppeteer.ElementHandle) => {
-  return $(textContent, root, 'pierceShadowText');
+  return await $(textContent, root, 'pierceShadowText');
 };
 
 /**
@@ -233,7 +233,7 @@ export const $textContent = async (textContent: string, root?: puppeteer.Element
  * @param root The root of the search.
  */
 export const $$textContent = async (textContent: string, root?: puppeteer.ElementHandle) => {
-  return $$(textContent, root, 'pierceShadowText');
+  return await $$(textContent, root, 'pierceShadowText');
 };
 
 export const timeout = (duration: number) => new Promise(resolve => setTimeout(resolve, duration));
@@ -247,7 +247,7 @@ export const getTextContent =
 export const getAllTextContents =
     async(selector: string, root?: puppeteer.JSHandle, handler = 'pierce'): Promise<Array<string|null>> => {
   const allElements = await $$(selector, root, handler);
-  return Promise.all(allElements.map(e => e.evaluate(e => e.textContent)));
+  return await Promise.all(allElements.map(e => e.evaluate(e => e.textContent)));
 };
 
 /**
@@ -466,7 +466,7 @@ export const goToResourceWithCustomHost = async (host: string, path: string) =>
   await goTo(`${getResourcesPath(host)}/${path}`);
 };
 
-export const getResourcesPath = (host: string = 'localhost') => {
+export const getResourcesPath = (host = 'localhost') => {
   return `https://${host}:${getTestServerPort()}/test/e2e/resources`;
 };
 
@@ -579,7 +579,7 @@ export const selectTextFromNodeToNode = async (
 
     document.execCommand('copy');
 
-    return navigator.clipboard.readText();
+    return await navigator.clipboard.readText();
   }, await from, await to, direction);
 };
 
@@ -736,7 +736,7 @@ export const hasClass = async (element: puppeteer.ElementHandle<Element>, classn
 
 export const waitForClass = async (element: puppeteer.ElementHandle<Element>, classname: string) => {
   await waitForFunction(async () => {
-    return hasClass(element, classname);
+    return await hasClass(element, classname);
   });
 };
 
@@ -843,7 +843,7 @@ export async function raf(page: puppeteer.Page): Promise<void> {
 export async function readClipboard() {
   const {frontend, browser} = getBrowserAndPages();
   await browser.defaultBrowserContext().overridePermissions(frontend.url(), ['clipboard-read']);
-  const clipboard = await frontend.evaluate(async () => navigator.clipboard.readText());
+  const clipboard = await frontend.evaluate(async () => await navigator.clipboard.readText());
   await browser.defaultBrowserContext().clearPermissionOverrides();
   return clipboard;
 }
diff --git a/test/shared/screenshots.ts b/test/shared/screenshots.ts
index a5ce303607..11210d3638 100644
--- a/test/shared/screenshots.ts
+++ b/test/shared/screenshots.ts
@@ -79,7 +79,8 @@ export const assertElementScreenshotUnchanged = async (
   if (platform !== 'linux') {
     return;
   }
-  return assertScreenshotUnchangedWithRetries(element, fileName, maximumDiffThreshold, DEFAULT_RETRIES_COUNT, options);
+  return await assertScreenshotUnchangedWithRetries(
+      element, fileName, maximumDiffThreshold, DEFAULT_RETRIES_COUNT, options);
 };
 
 const assertScreenshotUnchangedWithRetries = async (
@@ -230,7 +231,7 @@ interface ImageDiff {
 }
 
 async function imageDiff(golden: string, generated: string) {
-  return new Promise<ImageDiff>(async (resolve, reject) => {
+  return await new Promise<ImageDiff>(async (resolve, reject) => {
     try {
       const imageDiff: ImageDiff = {rawMisMatchPercentage: 0, diffPath: ''};
       const diffText = await execImageDiffCommand(`${IMAGE_DIFF_BINARY} --histogram ${golden} ${generated}`);
@@ -256,7 +257,7 @@ async function imageDiff(golden: string, generated: string) {
 }
 
 async function execImageDiffCommand(cmd: string) {
-  return new Promise<string>((resolve, reject) => {
+  return await new Promise<string>((resolve, reject) => {
     let commandOutput = '';
     try {
       commandOutput = childProcess.execSync(cmd, {encoding: 'utf8'});