Hello together,
it works well on ubuntu:
sudo add-apt-repository ppa:x2go/nightly sudo add-apt-repository ppa:x2go/ppa sudo apt update sudo apt install x2gohtmlclient
Documentation is extended for debian and ubuntu: https://wiki.x2go.org/doku.php/wiki:advanced:x2gohtmlclient
Best Regards, Juri Grabowski