After installing home-manager on Ubuntu 24.04, I add keybase using home-manager. It seems to go well, however, in the kbfs.service I can see;
[WARN kbfs mounter.go:41] 011 KBFS failed to FUSE mount at /home/matstage//home/matstage/keybase: fusermount: exec: “fusermount”: executable file not found in $PATH
It might do some bind mounting for container stuff. fusermount has to be installed by root because it requires setuid, so home-mamager can’t do it (NixOS has a special option for this that does some fancy stuff home-manager cannot).
Installing fusermount with apt is probably the way to go here.