I prefer 'rexcode' for the attribute name.

I share Serhiy's  reservations.  When people write code that depends on CPython implementation details, even though documented as such, the existence of such code becomes a drag on change, especially when details have been stable for awhile.  I just saw this used as an argument against one of the proposed bytecode/wordcode changes. "It would break current 3rd party code." It also came up a few years ago with randomizing hashes (and dict iteration order).

Jelle, can one access the 'rexcode' via ctypes?  Is so, I think an re disassembler with docs would be a good pypi module.  Maybe you could also make it work with Barnett's regex module.