Looks like we discovered it at essentially the same time, and in essentially the same way. If the pth file didn't trigger a fork-bomb like behavior, this might have stayed undiscoverd for quite a bit longer.

Good thinking on asking Claude to walk you through on who to contact. I had no idea how to contact anyone related to PyPI, so I started by shooting an email to the maintainers and posting it on Hacker News.

While I'm not part of the security community, I think everyone who finds something like this, should be able to report it. There is no point in gatekeeping the reporting of serious security vulnerabilities.