[tardedmeme]

Anyone can run a git setup. You need git and SSH installed on a server and you need an SSH key for each user.

[gnabgib]

You don't need this. git and a local drive. git and a shared drive. git and an https engine (can be a plugin to apache/nginx, not a full github like solution). git and ssh but people use username/password.

Full github/gitlab: git and Gogs, Gitea, Forgejo.