In current CPython, unpacked keyword arguments must be strings but don’t have to be valid identifiers.

Discussion: https://discuss.python.org/t/supporting-or-not-invalid-identifiers-in-kwargs/17147

Messages from Guido (creator of the language) and core developers show that this behaviour is desired and will not be changed.

The issue is whether this is a CPython (stable) implementation detail, in which case docs could be clarified with the fix backported, or if it’s time to make it a guaranteed part of the language, binding for other implementations, starting from 3.11 or 3.12.

I have not found where the doc should be improved; arguments and parameters are discussed in glossary, library reference, etc. but I don’t know where is one complete, authoritative explanation of unpacked keyword params.