The account behind it was renamed from LINUXexpert-org to jcoffey-dev,
and GitHub does not redirect the old name: github.com/sponsors/
LINUXexpert-org answers 404 while the new one answers 200. So the
Sponsor button on this repository has been leading nowhere.
Worth fixing rather than leaving to redirect, because a released
username can be registered by anyone -- a stale link stops being a dead
end and starts being someone else's page.