Turns out there’s no need to speculate. Someone pointed out on GH [0] that the AI was literally prompted to copy the existing code:
> *Context:* The registry maps every supported encoding to its metadata. Era assignments MUST match chardet 6.0.0's `chardet/metadata/charsets.py` at https://raw.githubusercontent.com/chardet/chardet/f0676c0d6a...
> Fetch that file and use it as the authoritative reference for which encodings belong to which era. Do not invent era assignments.
[0] https://github.com/chardet/chardet/issues/327#issuecomment-4...
That's data, not code.
It’s a python file from chardet 6, doesn’t matter what you think it does. It clearly wasn’t a clean room reimplementation.