> I'll make a test repo on my GitLab account to try it out.

It works easily enough.

You have to make a "Personal access token" on GitHub and stick it into
the Password field in GitLab. The token needs to be given write access
to all your GitHub repos -- I can't find a way to give permission on a
finer granularity.

Is everyone OK with keeping the master copy of the registry in GitLab?

Should we set up a schememirror organization on github and mirror the
registry (as well as possibly other Scheme-related things) there?