It would have been nice to have a bit more information:

does it have a frontend? If so what does it look like? What does “somewhat compatible with mastodon” mean? Which features are working?

@lionel@lemmy.coupou.fr

This software is Work in progress, found it here in the comments : https://lobste.rs/s/xvvjza/playing_with_activitypub#c_spnt25

The page shows what works and what does not work. I think it is similar as GoToSocial, having no front end.