Stumpy is ready for use, for anyone who wants to use it. If you’re working on an application that sends email and you’d like to test that feature, you may find this useful.
In other news, searching for “pop3 client library” leads me to believe that every developer for macOS thinks that Apple Mail is the absolute bees knees and there’s just no reason anyone would want to receive email in any other way. Unless maybe they wanted to use python. Which is just mystifying to me, because come on!