angular · alxhub · May 21, 2026
diff --git a/contributing-docs/google-markers.md b/contributing-docs/google-markers.md
@@ -0,0 +1,95 @@
+# Angular Google Sync Comment Markers Guide
+
+This document describes the comment-based markers used in the Angular repository to manage the synchronization process between the public GitHub repository and Google's internal codebase (google3).
+
+As an Angular contributor, you will occasionally encounter these markers in the codebase. Most external contributors will never need to **write** these markers themselves. Instead, this guide exists to explain what these markers mean and why they are in the code when you run into them.
+
+These tags are necessary because Google's internal codebase builds and integrates Angular in a slightly different configuration than the public NPM packages. For example, Google may require certain APIs to remain public internally for integration purposes, or might need to bypass public-only configurations. These markers allow the automated sync tooling to adjust the code seamlessly during the import process.
+
+---
+
+## Reference Table
+
+The following markers are processed during the synchronization to Google's internal codebase:
+
+| Marker                                        | Type        | Action in Google's Codebase                 | Intended Use Case                                                                           |
+| :-------------------------------------------- | :---------- | :------------------------------------------ | :------------------------------------------------------------------------------------------ |
+| **`// 3p-only`**                              | Single-line | **Strip**: Deletes the entire line          | Remove imports or calls that only exist in the public version.                              |
+| **`// 3p-only-start`** / **`// 3p-only-end`** | Block       | **Strip**: Deletes the entire block         | Remove larger chunks of public-only code (e.g., benchmarking suites, public-only adapters). |
+| **`// g3-only`**                              | Single-line | **Insert**: Uncomments the rest of the line | Export Google-internal symbols or activate Google-specific configurations.                  |
+| **`// g3-only-start`** / **`// g3-only-end`** | Block       | **Insert**: Uncomments every line inside    | Add larger Google-specific functions or class definitions.                                  |
+
+---
+
+## Detailed Marker Explanations & Examples
+
+### 1. Removing Single Lines (`// 3p-only`)
+
+This tag is appended at the end of a line comment to completely remove that line when the code is synced internally to Google.
+
+- **GitHub Source**:
+  ```typescript
+  import {ExternalBenchmarkRunner} from './benchmarks'; // 3p-only
+  ```
+- **Google's Internal Codebase**:
+  _(The line is completely removed)_
+
+---
+
+### 2. Removing Blocks of Code (`// 3p-only-start` / `// 3p-only-end`)
+
+Blocks of code that should only run in the public version are surrounded by these markers. The entire block is stripped during the sync.
+
+- **GitHub Source**:
+  ```typescript
+  // 3p-only-start
+  export function initializeDevTools() {
+    console.log('Setting up external devtools...');
+    setupExternalDebugger();
+  }
+  // 3p-only-end
+  ```
+- **Google's Internal Codebase**:
+  _(The entire block, including markers, is completely removed)_
+
+---
+
+### 3. Activating Single Lines (`// g3-only`)
+
+Google-specific code is written as a comment and prefixed with `// g3-only`. The sync tooling uncomments this line when importing it into Google's codebase.
+
+- **GitHub Source**:
+  ```typescript
+  // g3-only export {ForeignComponent} from './interface/foreign_component';
+  ```
+- **Google's Internal Codebase**:
+  ```typescript
+  export {ForeignComponent} from './interface/foreign_component';
+  ```
+
+---
+
+### 4. Activating Blocks of Code (`// g3-only-start` / `// g3-only-end`)
+
+Larger blocks of Google-specific code are commented out line-by-line and wrapped in the `g3-only` start/end markers. The sync tooling strips the markers and uncomments all lines in between.
+
+- **GitHub Source**:
+  ```typescript
+  // g3-only-start
+  // export function getGoogleSpecificConfig() {
+  //   return {
+  //     enableInternalLogging: true,
+  //     useInternalDatabase: true,
+  //   };
+  // }
+  // g3-only-end
+  ```
+- **Google's Internal Codebase**:
+  ```typescript
+  export function getGoogleSpecificConfig() {
+    return {
+      enableInternalLogging: true,
+      useInternalDatabase: true,
+    };
+  }
+  ```
diff --git a/packages/compiler-cli/index.ts b/packages/compiler-cli/index.ts
@@ -18,6 +18,7 @@ export * from './src/perform_compile';
 // TODO(tbosch): remove this once usages in G3 are changed to `CompilerOptions`
 export {CompilerOptions as AngularCompilerOptions} from './src/transformers/api';
 
+// 3p-only-start
 // Internal exports needed for packages relying on the compiler-cli.
 // TODO: Remove this when the CLI has switched to the private entry-point.
 export * from './private/tooling';
@@ -27,6 +28,7 @@ export * from './private/hybrid_analysis';
 // Exposed as they are needed for relying on the `linker`.
 export * from './src/ngtsc/logging';
 export * from './src/ngtsc/file_system';
+// 3p-only-end
 
 // Exports for dealing with the `ngtsc` program.
 export {NgTscPlugin, PluginCompilerHost} from './src/ngtsc/tsc_plugin';

diff --git a/packages/compiler-cli/src/ngtsc/core/src/feature_detection.ts b/packages/compiler-cli/src/ngtsc/core/src/feature_detection.ts
@@ -8,7 +8,7 @@
 
 // Note: semver isn't available internally so this import will be commented out.
 // When adding more dependencies here, the caretaker may have to update a patch internally.
-import semver from 'semver';
+import semver from 'semver'; // 3p-only
 
 /**
  * Whether a version of `@angular/core` supports a specific feature.
@@ -23,5 +23,6 @@ export function coreVersionSupportsFeature(coreVersion: string, minVersion: stri
     return true;
   }
 
-  return semver.satisfies(coreVersion, minVersion, {includePrerelease: true});
+  // g3-only return true;
+  return semver.satisfies(coreVersion, minVersion, {includePrerelease: true}); // 3p-only
 }
diff --git a/packages/compiler/src/legacy_optional_chaining_default.ts b/packages/compiler/src/legacy_optional_chaining_default.ts
@@ -11,4 +11,5 @@
  *
  * This is extracted in order to be patched in G3.
  */
-export const LEGACY_OPTIONAL_CHAINING_DEFAULT = false;
+// g3-only export const LEGACY_OPTIONAL_CHAINING_DEFAULT = true;
+export const LEGACY_OPTIONAL_CHAINING_DEFAULT = false; // 3p-only
diff --git a/packages/core/primitives/dom-navigation/testing/fake_navigation.ts b/packages/core/primitives/dom-navigation/testing/fake_navigation.ts
@@ -6,6 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
+// 3p-only-start
 import {
   NavigationNavigateOptions,
   NavigationTypeString,
@@ -21,6 +22,7 @@ import {
   NavigationDestination,
   Navigation,
 } from '../src/navigation_types';
+// 3p-only-end
 
 /**
  * Fake implementation of user agent history and navigation behavior. This is a
@@ -616,13 +618,13 @@ export class FakeNavigation implements Navigation {
 
   set oncurrententrychange(
     _handler: // tslint:disable-next-line:no-any
-    ((this: Navigation, ev: NavigationCurrentEntryChangeEvent) => any) | null,
+      ((this: Navigation, ev: NavigationCurrentEntryChangeEvent) => any) | null,
   ) {
     throw new Error('unimplemented');
   }
 
   get oncurrententrychange(): // tslint:disable-next-line:no-any
-  ((this: Navigation, ev: NavigationCurrentEntryChangeEvent) => any) | null {
+    ((this: Navigation, ev: NavigationCurrentEntryChangeEvent) => any) | null {
     throw new Error('unimplemented');
   }
 

diff --git a/packages/core/primitives/event-dispatch/src/event_contract_defines.ts b/packages/core/primitives/event-dispatch/src/event_contract_defines.ts
@@ -10,4 +10,5 @@
  * @define Support for the non-bubbling mouseenter and mouseleave events.  This
  * flag can be overridden in a build rule.
  */
-export const MOUSE_SPECIAL_SUPPORT = false;
+// g3-only export const MOUSE_SPECIAL_SUPPORT = goog.define('jsaction.EventContract.MOUSE_SPECIAL_SUPPORT', false,);
+export const MOUSE_SPECIAL_SUPPORT = false; // 3p-only
diff --git a/packages/core/primitives/event-dispatch/src/event_dispatcher.ts b/packages/core/primitives/event-dispatch/src/event_dispatcher.ts
@@ -14,7 +14,7 @@ import {UnrenamedEventContract} from './eventcontract';
 import {Restriction} from './restriction';
 
 // Necessary to make the `ngDevMode` global types available.
-import '../../../src/util/ng_dev_mode';
+import '../../../src/util/ng_dev_mode'; // 3p-only
 
 /**
  * A replayer is a function that is called when there are queued events, from the `EventContract`.

diff --git a/packages/core/src/change_detection/constants.ts b/packages/core/src/change_detection/constants.ts
@@ -38,6 +38,8 @@ export enum ChangeDetectionStrategy {
    * explicitly deactivated.
    * @deprecated Use `Eager` instead.
    */
+  // 3p-only-start
   // tslint:disable-next-line:no-duplicate-enum-values
   Default = 1,
+  // 3p-only-end
 }
diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
@@ -76,6 +76,7 @@ export {
   TRANSLATIONS,
   TRANSLATIONS_FORMAT,
 } from './i18n/tokens';
+// g3-only export {ForeignComponent} from './interface/foreign_component';
 export {AbstractType, Type} from './interface/type';
 export * from './linker';
 export * from './linker/ng_module_factory_loader_impl';
@@ -111,6 +112,7 @@ export {
   outputBinding,
   twoWayBinding,
 } from './render3/dynamic_bindings';
+// g3-only export {foreignImport} from './render3/foreign_import';
 export {createEnvironmentInjector, createNgModule} from './render3/ng_module_ref';
 export {publishExternalGlobalUtil as ɵpublishExternalGlobalUtil} from './render3/util/global_utils';
 export * from './resource';

diff --git a/packages/core/src/i18n/tokens.ts b/packages/core/src/i18n/tokens.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-/// <reference path="../../../goog.d.ts" />
+/// <reference path="../../../goog.d.ts" /> // 3p-only
 
 import {InjectionToken} from '../di/injection_token';
 import {inject} from '../di/injector_compatibility';

diff --git a/packages/core/src/metadata/directives.ts b/packages/core/src/metadata/directives.ts
@@ -646,7 +646,7 @@ export interface Component extends Directive {
    * The foreignImports property specifies components from other frameworks that can be used
    * within this component's template.
    *
-   * @internal
+   * @internal // 3p-only
    */
   foreignImports?: ForeignComponent[];
 
@@ -657,7 +657,7 @@ export interface Component extends Directive {
    * which bring symbols used in the `deferredImports` don't contain other symbols.
    *
    * Note: this is an internal-only field, use regular `@Component.imports` field instead.
-   * @internal
+   * @internal // 3p-only
    */
   deferredImports?: (Type<any> | ReadonlyArray<any>)[];
 

diff --git a/packages/core/src/render3/jit/directive.ts b/packages/core/src/render3/jit/directive.ts
@@ -376,7 +376,8 @@ export function directiveMetadata(type: Type<any>, metadata: Directive): R3Direc
 
   return {
     name: type.name,
-    legacyOptionalChaining: false,
+    // g3-only legacyOptionalChaining: true,
+    legacyOptionalChaining: false, // 3p-only
     type: type,
     selector: metadata.selector !== undefined ? metadata.selector : null,
     host: metadata.host || EMPTY_OBJ,

diff --git a/packages/core/src/render3/util/global_utils.ts b/packages/core/src/render3/util/global_utils.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-/// <reference path="../../../../goog.d.ts" />
+/// <reference path="../../../../goog.d.ts" /> // 3p-only
 
 import {assertDefined} from '../../util/assert';
 import {global} from '../../util/global';

diff --git a/packages/core/src/util/ng_i18n_closure_mode.ts b/packages/core/src/util/ng_i18n_closure_mode.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-/// <reference path="../../../goog.d.ts" />
+/// <reference path="../../../goog.d.ts" /> // 3p-only
 
 import {global} from './global';
 

diff --git a/packages/core/src/webmcp/declare_tool.ts b/packages/core/src/webmcp/declare_tool.ts
@@ -6,7 +6,8 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import type {JsonSchemaForInference} from '../../third_party/@mcp-b/webmcp-types';
+// g3-only import type {JsonSchemaForInference} from '@mcp-b/webmcp-types';
+import type {JsonSchemaForInference} from '../../third_party/@mcp-b/webmcp-types'; // 3p-only
 import {assertInInjectionContext, inject, Injector, runInInjectionContext} from '../di';
 import type {ModelContext, ToolDescriptor} from './types';
 import {DestroyRef} from '../linker';

diff --git a/packages/core/src/webmcp/provide_tools.ts b/packages/core/src/webmcp/provide_tools.ts
@@ -6,7 +6,8 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import type {JsonSchemaForInference} from '../../third_party/@mcp-b/webmcp-types';
+// g3-only import type {JsonSchemaForInference} from '@mcp-b/webmcp-types';
+import type {JsonSchemaForInference} from '../../third_party/@mcp-b/webmcp-types'; // 3p-only
 import {EnvironmentProviders, makeEnvironmentProviders, provideEnvironmentInitializer} from '../di';
 import {declareExperimentalWebMcpTool} from './declare_tool';
 import type {ToolDescriptor} from './types';

diff --git a/packages/core/src/webmcp/types.ts b/packages/core/src/webmcp/types.ts
@@ -6,10 +6,18 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
+// g3-only-start
+// import type {
+//   InferArgsFromInputSchema,
+//   JsonSchemaForInference,
+// } from '@mcp-b/webmcp-types';
+// g3-only-end
+// 3p-only-start
 import type {
   InferArgsFromInputSchema,
   JsonSchemaForInference,
 } from '../../third_party/@mcp-b/webmcp-types';
+// 3p-only-end
 
 /**
  * The client context of a given WebMCP tool execution.

diff --git a/packages/forms/src/directives/shared.ts b/packages/forms/src/directives/shared.ts
@@ -65,7 +65,8 @@ export type SetDisabledStateOption = 'whenDisabledForLegacyCode' | 'always';
 /**
  * Whether to use the fixed setDisabledState behavior by default.
  */
-export const setDisabledStateDefault: SetDisabledStateOption = 'always';
+// g3-only export const setDisabledStateDefault: SetDisabledStateOption = 'whenDisabledForLegacyCode';
+export const setDisabledStateDefault: SetDisabledStateOption = 'always'; // 3p-only
 
 export function controlPath(name: string | null, parent: ControlContainer): string[] {
   return [...parent.path!, name!];

diff --git a/packages/platform-browser/animations/src/module.ts b/packages/platform-browser/animations/src/module.ts
@@ -11,7 +11,8 @@ import {
   Provider,
   ɵperformanceMarkFeature as performanceMarkFeature,
 } from '@angular/core';
-import {BrowserModule} from '../../index';
+// g3-only import {BrowserModule} from '@angular/platform-browser';
+import {BrowserModule} from '../../index'; // 3p-only
 
 import {BROWSER_ANIMATIONS_PROVIDERS, BROWSER_NOOP_ANIMATIONS_PROVIDERS} from './providers';
 

diff --git a/packages/platform-browser/src/dom/util.ts b/packages/platform-browser/src/dom/util.ts
@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-/// <reference path="../../../goog.d.ts" />
+/// <reference path="../../../goog.d.ts" /> // 3p-only
 
 import {ɵglobal as global} from '@angular/core';
 

diff --git a/packages/platform-browser/testing/src/browser.ts b/packages/platform-browser/testing/src/browser.ts
@@ -8,7 +8,8 @@
 import {ɵprovideFakePlatformNavigation} from '@angular/common/testing';
 import {APP_ID, createPlatformFactory, NgModule, StaticProvider, PlatformRef} from '@angular/core';
 import {TestComponentRenderer} from '@angular/core/testing';
-import {BrowserModule, platformBrowser} from '../../index';
+// g3-only import {BrowserModule, platformBrowser} from '@angular/platform-browser';
+import {BrowserModule, platformBrowser} from '../../index'; // 3p-only
 import {DOMTestComponentRenderer} from './dom_test_component_renderer';
 
 /**

diff --git a/packages/platform-server/src/domino_adapter.ts b/packages/platform-server/src/domino_adapter.ts
@@ -9,7 +9,8 @@
 import {ɵsetRootDomAdapter as setRootDomAdapter} from '@angular/common';
 import {ɵBrowserDomAdapter as BrowserDomAdapter} from '@angular/platform-browser';
 
-import domino from '../third_party/domino/bundled-domino';
+// g3-only import domino from 'domino';
+import domino from '../third_party/domino/bundled-domino'; // 3p-only
 
 export function setDomTypes() {
   // Make all Domino types available in the global env.

diff --git a/packages/router/src/router_state.ts b/packages/router/src/router_state.ts
@@ -240,7 +240,8 @@ export class ActivatedRoute {
 
 export type ParamsInheritanceStrategy = 'emptyOnly' | 'always';
 
-export const DEFAULT_PARAMS_INHERITANCE_STRATEGY: ParamsInheritanceStrategy = 'always';
+// g3-only export const DEFAULT_PARAMS_INHERITANCE_STRATEGY: ParamsInheritanceStrategy = 'emptyOnly';
+export const DEFAULT_PARAMS_INHERITANCE_STRATEGY: ParamsInheritanceStrategy = 'always'; // 3p-only
 
 /** @internal */
 export type Inherited = {

diff --git a/packages/types.d.ts b/packages/types.d.ts
@@ -11,7 +11,7 @@
 // This file contains all ambient imports needed to compile the packages/ source code
 
 /// <reference lib="es2015" />
-/// <reference path="./goog.d.ts" />
+/// <reference path="./goog.d.ts" /> // 3p-only
 /// <reference path="./system.d.ts" />
 
 // Do not included "node" and "jasmine" types here as we don't

diff --git a/packages/zone.js/lib/zone.ts b/packages/zone.js/lib/zone.ts
@@ -31,6 +31,11 @@ declare global {
   const Zone: ZoneType;
   type Zone = _Zone;
   type ZoneType = _ZoneType;
+
+  // g3-only-start
+  // /** This local mod is kept in place so Zone can check the NodeJS `global` variable. */
+  // var global: {};
+  // g3-only-end
   type _PatchFn = PatchFn;
   type _ZonePrivate = ZonePrivate;
   type _ZoneFrame = ZoneFrame;