The answer to the PII issues is hence not restrictions in userdb, the answer is proper app sandboxing. And that even already exists in flatpak! It restricts access to $HOME already, and to userdb too! And that’s the way to do it!

I don’t use flatpak. I don’t like it. Linux is about choice and I choose not to use that.

Hence, just embrace app sandboxing! And if you come to me and say “hey, I run all my apps without sandboxing, but i want the birthday hidden anyway” then I can only say, your model is really really broken. Fix your security model first, then come back.

In the words of the great Linus Torvalds, go fuck yourself.