A non-trivial minority of the time, they don't support IPv4 either!
IPv1, IPv2, and IPv3 were very early experimental versions of the Internet Protocol developed in the 1970s during the ARPANET era (the precursor to the modern internet). Has anyone tried to find out if GitHub is reliable on those?
GitHub is at the point where it immediately rate limits me if I try to look at a project's commit history without being logged in, as in the first time I even open a single URL to the commit history, I get "Too Many Requests" from GitHub thrown at me. I don't know if my work's antivirus stack is causing GitHub to be suspicious of me, but it's definitely egregious.