The code appears to be unavailable. This includes not just wordgard but all the ProseMirror code as well.
If the motivation for moving off GitHub was "GH is down too much", it might be worth tracking how many 9's of uptime is lost in the self-hosted case.
Works for me:
$ git clone https://code.haverbeke.berlin/wordgard/wordgard.git
Cloning into 'wordgard'...
remote: Enumerating objects: 8274, done.
remote: Counting objects: 100% (8274/8274), done.
remote: Compressing objects: 100% (4747/4747), done.
remote: Total 8274 (delta 6049), reused 5002 (delta 3464), pack-reused 0 (from 0)
Receiving objects: 100% (8274/8274), 1.61 MiB | 2.93 MiB/s, done.
Resolving deltas: 100% (6049/6049), done.Were you meaning it was unavailable temporarily?
Maybe something changed in the meantime, but I'm seeing what appears to be the code for it here: https://code.haverbeke.berlin/wordgard/wordgard/src/branch/m...
I've had another report like this (they claimed it had been down for days). But I haven't noticed anything wrong with it (and I'm using it a lot). What did 'down' look like?
Also, though GitHub's lack of reliability was part of the motivation to self-host, it was only a minor factor. The way they are trying to make Copilot a thing, at the cost of everything else, the way they handle US sanctions by blocking everybody from entire countries, and the way the web interface feels ever more heavyweight and sloppy were also factors.