src/vs/platform/native/electron-main/nativeHostMainService.ts/NativeHostMainService/updateTitleBarOverlay
class NativeHostMainService:	async updateTitleBarOverlay(windowId: number | undefined, options: { height?: number; backgroundColor?: string; foregroundColor?: string }): Promise<void> {
		const window = this.windowById(windowId);
		if (window?.win) {
			window.win.setTitleBarOverlay({
				color: options.backgroundColor,
				symbolColor: options.foregroundColor,
				height: options.height ? options.height - 1 : undefined // account for window border
			});
		}
	}