Personally i've been using GitLab for my own projects for many years
now, and i also pay for the even more obscure sourcehut at
https://sr.ht/ (i can recommend both). PyPNG, being a project that
other people actually used, was among the last to move.
Practically speaking PyPNG has been
https://gitlab.com/drj11/pypng for
about a year, i just forgot that we have this e-mail list to announce
that to.
I've archived the GitHub repo.
David Jones
PyPNG maintainer