The documentation for the encodings.idna module contains no indicator that the RFC it supports has been obsoleted by another RFC: https://docs.python.org/3.10/library/codecs.html#module-encodings.idna
I'm sure this is obvious when you know your RFCs, but when just looking at the docs, it's easy to miss. In #msg379674, Marc-Andre suggested to fix the situation by deprecating or updating IDNA support. I'd like to propose to add a warning message in the meantime, pointing out the newer RFC and linking to the idna package on PyPI (if links to PyPI packages are alright in the docs?)