[meonkeys]

For what part(s) of github?

Free as in freedom?

Many other tools/platforms provide decent source control and issue tracking. Nothing else has the FOSS project market share of github, and this matters especially when you're looking for the canonical home of a project and trying to judge how popular/active/viable it is (stars/commits/issues/PRs).

If you want exposure and participation for your FOSS project, it's harder to not use github.

FWIW, Forgejo does the source control stuff well. I love it for self-hosted local mirrors.