src/vs/platform/windows/electron-main/windowsMainService.ts/WindowsMainService/registerListeners
class WindowsMainService:	private registerListeners(): void {

		// Signal a window is ready after having entered a workspace
		this._register(this.workspacesManagementMainService.onDidEnterWorkspace(event => this._onDidSignalReadyWindow.fire(event.window)));

		// Update valid roots in protocol service for extension dev windows
		this._register(this.onDidSignalReadyWindow(window => {
			if (window.config?.extensionDevelopmentPath || window.config?.extensionTestsPath) {
				const disposables = new DisposableStore();
				disposables.add(Event.any(window.onDidClose, window.onDidDestroy)(() => disposables.dispose()));

				// Allow access to extension development path
				if (window.config.extensionDevelopmentPath) {
					for (const extensionDevelopmentPath of window.config.extensionDevelopmentPath) {
						disposables.add(this.protocolMainService.addValidFileRoot(extensionDevelopmentPath));
					}
				}

				// Allow access to extension tests path
				if (window.config.extensionTestsPath) {
					disposables.add(this.protocolMainService.addValidFileRoot(window.config.extensionTestsPath));
				}
			}
		}));
	}