m5l.eu is a Fediverse instance that uses the ActivityPub protocol. In other words, users at this host can communicate with people that use software like Mastodon, Pleroma, Friendica, etc. all around the world.
This server runs the snac software and there is no automatic sign-up process.
I'm running Forgejo in a container now to isolate SSH access, but I also had it installed directly for some time.
This is what I use now, after #selfhosting Apache SVN, Perforce, Tuleap, RhodeCode, Phorge and Gitea so far.