> Not for builtin functions, but it's unclear to me why the API of
> builtin functions should be different from that of Python functions
> (except, as I said, for the existence of byte code).

I really don't follow you.  You seem to be saying that __text_signature__ is a bad idea, and keep talking about existing
APIs that provide for the same functionality, but you decline to name
specifics.

Be specific.  Let's say we remove __text_signature__.  How do we
now write a C extension in a way that we can have introspection
information for its callables?

If __text_signature__ is redundant with existing APIs, then we should remove it now before 3.4 ships.