src/vs/workbench/services/extensionManagement/common/webExtensionsScannerService.ts/WebExtensionsScannerService/scanUserExtensions
class WebExtensionsScannerService:	async scanUserExtensions(): Promise<IExtension[]> {
		const extensions = [];

		// Static extensions defined through `staticExtensions` API
		const staticExtensions = await this.staticExtensionsPromise;
		extensions.push(...staticExtensions);

		// Custom builtin extensions defined through `additionalBuiltinExtensions` API
		const customBuiltinExtensions = await this.customBuiltinExtensionsPromise;
		extensions.push(...customBuiltinExtensions);

		// User Installed extensions
		const installedExtensions = await this.scanInstalledExtensions();
		extensions.push(...installedExtensions);

		return extensions;
	}