I just discovered on x2goserver-18.104.22.168, that if you depclean x11-apps/xkbcomp out of your headless system (vserver), keyboard configurations will fail to work.
Clearest symptom: AltGr won't be recognized in X2Go sessions anymore.
Looking at deps, `setxkbmap` nor `xkbcomp` is listed anywhere.
`/usr/bin/x2gosetkeyboard` uses `setxkbmap` extensively, so it does look like missing dependency definitions.
Possibly related: https://bugs.x2go.org/cgi-bin/bugreport.cgi?bug=1160