When trying to look at the last couple of issues in #9415, I saw this (from pytest-flake8):

 PytestDeprecationWarning: <class 'pytest_flake8.Flake8Item'> is not using a cooperative constructor and only takes {'fspath', 'parent'}

It took me a bit of guessing to know that the warning probably wants me to add **kwargs and pass it on. This was done as part of #8447, but it seems to me like it should have a section in the deprecation docs we could link to, as well as a dedicated changelog entry.