Gitea and Gogs are light-weight software that implement Git system, can run on ARM minicomputers like Raspberry Pi.
Gogs and Gitea are Open Source, single-binary Go implementations of a Github-like git repository hosting system which I can use privately or in teams. Both are light on system requirements, contrary to a pretty large and quite popular Open Source Java implementation of a similar utility.
Source: Jan-Piet Mens :: Gogs and Gitea
Another comparison between Gitea and Gogs:
Gogs is managed by a single person, who is the original author. The community asked many times to share responsibility but this was never accepted. So yes, this is the reason why the project was forked. Read more on https://blog.gitea.io/2016/12/welcome-to-gitea/
Gitea itself published the comparison between Gitea, Gogs and other self-maintained git hosting software (Github, Gitlab, BitBucket…):