The buffer protocol is a low level C protocol, but even if it doesn't expose a specific python API, it's currently not possible to say "this object implements the buffer protocol" in Python

This might be useful for some applications, including PEP-484 typing hints. It would be useful to have a collections.abc.Buffer which already registers the types that already support the protocol (bytes, strings, array.array, struct, mmap, ctype arrays/pointers, etc)