It appears the github releases are not able to be installed via other tools (in this case, ajour)

That's weird, it was possible before and I'm still using the same github actions for version releases.

Ajour has been unmaintained for quite a while now, maybe there was a change in the github API? Have you made sure that other addons are still working? From what I can tell, the releases can be downloaded just fine from the release page in the github frontend.

Since ajour has been unmaintained for a while and I haven't received any other reports, I'll go ahead and close this for now. If this is still a problem for you, feel free to reopen.