[Python-Dev] Are undocumented functions part of the stable ABI?

Hello, I have a question about PEP 384: can undocumented functions ever be considered as part of the stable ABI? With undocumented, I mean not appearing in the "Python/C API Reference Manual". Whatever the answer to this question is, it would be good to make it explicit in PEP 384. I am in particular asking about functions starting with PyCFunction_ appearing in Include/methodobject.h Thanks, Jeroen.