*trying out https://notabug.org/ as possible new home for !gnusocial* @postblue recommended it.
Apparently a git repo written in Go (instead of the usual Ruby) and very, very newly started. So who knows how long they can keep running it?
The software is MIT licensed (not much better than #gitlab though, but at least #notabug don't have a separate commercially licensed software - hinting that the community edition is intentionally crippled).

It's either finding an MIT-ish licensed software hosted by a third party, or we host something ourselves (/use Savannah). I doubt anyone would bother overtaking the Gitorious AGPL source code even if that'd be the best thing to do ideologically...