Proof theory is a branch of mathematical logic which treats proofs just like other mathematical objects, like numbers and sets. It's an extremely technical field, involving Gödel-numberings, derivability conditions, reflection principles, and transfinite ordinals (oh my!). Contrary to what seems to be a common belief on Math.SE, it's NOT about what makes a good and rigorous proof, how to write proofs, and the general subject of the role proofs play in pure mathematics.
Yet that seems to be the meaning people are assuming when they select the proof-theory tag. It seems like almost all the questions with this tag are mislabeled. I'm aware that if you hover over a tag, descriptions pop up, but a lot of people, especially first-time users, may not notice them. So would it be possible to do some kind of cleanup of the questions associated with this tag?