Arch Linux have used their own gitlab instance for a long time (though with mirrors to GitHub). Debian and Fedora have both run their own infra for git for a long time. Not sure about other distros. I was surprised Gentoo used GitHub at all.
Pretty sure several of these distros started doing this with cvs or svn way back before git became popular even.
Pretty sure several of these distros started doing this with cvs or svn way back before git became popular even.