src/vs/workbench/services/extensionManagement/browser/webExtensionsScannerService.ts/WebExtensionsScannerService/readCustomBuiltinExtensions
class WebExtensionsScannerService:	private async readCustomBuiltinExtensions(scanOptions?: ScanOptions): Promise<IScannedExtension[]> {
		const [customBuiltinExtensionsFromLocations, customBuiltinExtensionsFromGallery] = await Promise.all([
			this.getCustomBuiltinExtensionsFromLocations(scanOptions),
			this.getCustomBuiltinExtensionsFromGallery(scanOptions),
		]);
		const customBuiltinExtensions: IScannedExtension[] = [...customBuiltinExtensionsFromLocations, ...customBuiltinExtensionsFromGallery];
		await this.migrateExtensionsStorage(customBuiltinExtensions);
		return customBuiltinExtensions;
	}