src/vs/workbench/services/extensionManagement/browser/builtinExtensionsScannerService.ts/BuiltinExtensionsScannerService/constructor
class BuiltinExtensionsScannerService:	constructor(
		@IWorkbenchEnvironmentService environmentService: IWorkbenchEnvironmentService,
		@IUriIdentityService uriIdentityService: IUriIdentityService,
		@IExtensionResourceLoaderService private readonly extensionResourceLoaderService: IExtensionResourceLoaderService,
		@IProductService productService: IProductService,
		@ILogService private readonly logService: ILogService
	) {
		if (isWeb) {
			const nlsBaseUrl = productService.extensionsGallery?.nlsBaseUrl;
			// Only use the nlsBaseUrl if we are using a language other than the default, English.
			if (nlsBaseUrl && productService.commit && !Language.isDefaultVariant()) {
				this.nlsUrl = URI.joinPath(URI.parse(nlsBaseUrl), productService.commit, productService.version, Language.value());
			}

			const builtinExtensionsServiceUrl = FileAccess.asBrowserUri(builtinExtensionsPath);
			if (builtinExtensionsServiceUrl) {
				let bundledExtensions: IBundledExtension[] = [];

				if (environmentService.isBuilt) {
					// Built time configuration (do NOT modify)
					bundledExtensions = [/*BUILD->INSERT_BUILTIN_EXTENSIONS*/];
				} else {
					// Find builtin extensions by checking for DOM
					const builtinExtensionsElement = document.getElementById('vscode-workbench-builtin-extensions');
					const builtinExtensionsElementAttribute = builtinExtensionsElement ? builtinExtensionsElement.getAttribute('data-settings') : undefined;
					if (builtinExtensionsElementAttribute) {
						try {
							bundledExtensions = JSON.parse(builtinExtensionsElementAttribute);
						} catch (error) { /* ignore error*/ }
					}
				}

				this.builtinExtensionsPromises = bundledExtensions.map(async e => {
					const id = getGalleryExtensionId(e.packageJSON.publisher, e.packageJSON.name);
					const browserNlsBundleUris: { [language: string]: URI } = {};
					if (e.browserNlsMetadataPath) {
						if (this.nlsUrl) {
							browserNlsBundleUris[Language.value()] = uriIdentityService.extUri.joinPath(this.nlsUrl, id, 'main');
						}
						browserNlsBundleUris.en = uriIdentityService.extUri.resolvePath(builtinExtensionsServiceUrl!, e.browserNlsMetadataPath);
					}
					ImplicitActivationEvents.updateManifest(e.packageJSON);
					return {
						identifier: { id },
						location: uriIdentityService.extUri.joinPath(builtinExtensionsServiceUrl!, e.extensionPath),
						type: ExtensionType.System,
						isBuiltin: true,
						browserNlsBundleUris,
						manifest: e.packageNLS ? await this.localizeManifest(id, e.packageJSON, e.packageNLS) : e.packageJSON,
						readmeUrl: e.readmePath ? uriIdentityService.extUri.joinPath(builtinExtensionsServiceUrl!, e.readmePath) : undefined,
						changelogUrl: e.changelogPath ? uriIdentityService.extUri.joinPath(builtinExtensionsServiceUrl!, e.changelogPath) : undefined,
						targetPlatform: TargetPlatform.WEB,
						validations: [],
						isValid: true
					};
				});
			}
		}
	}