In some header of a not yet wrapped framework:
typedef float vector_float3 __attribute__((__ext_vector_type__(3)));
Types like this are not yet handled by PyObjC.
Research how these values are passed as arguments and returned (at least for x86_64)
Design Python representation (small float tuples?)
Implement this in pyobjc-core and/or libffi.
Add metadata annotation for these types