The output below shows that in 2.3a1, that module prefix string is discarded in favor of the name of the module which imports the extension module.
Look at revision 2.194 of Objects/typeobject.c. I changed some stuff in this area, but am far too fuzzy headed today to work out if it's likely to have affected you in this case... Cheers, M. -- I have no disaster recovery plan for black holes, I'm afraid. Also please be aware that if it one looks imminent I will be out rioting and setting fire to McDonalds (always wanted to do that) and probably not reading email anyway. -- Dan Barlow