Yes, exactly. Thanks for the clarifying question. :-)

Any kind of artifact in code: modules, functions, classes, arguments, variables...

Ones that used to annoy me were in the standard library, in particular the unitest module with camel-case functions (assertEqual and so on), I've seen this justified by it being old and predating the snake-case conventions, but surely assert_equal could have lived alongside the older names. Moot now that I've switched to pytest of course ...

Yeah, anything that contradict s PEP-8 conventions looks unnatural in Python. :-)