src/vs/base/node/shell.ts/getSystemShell
export async function getSystemShell(os: platform.OperatingSystem, env: platform.IProcessEnvironment): Promise<string> {
	if (os === platform.OperatingSystem.Windows) {
		if (platform.isWindows) {
			return getSystemShellWindows();
		}
		// Don't detect Windows shell when not on Windows
		return processes.getWindowsShell(env);
	}

	return getSystemShellUnixLike(os, env);
}