UNINSTALL
- Open a privileged cmd.exe
- lxrun /uninstall /full
- reboot
- sc stop lxssmanager
- rmdir /S %LOCALAPPDATA%\lxss
- uninstall from "Microsoft Store" (this deletes all your installation):
    - from the store "add to Start menu"
    - from the start menu right-click "uninstall"

optionalfeatures.exe : Open "Windows Features"