PyPy is no longer under active development, and has not released a Python3.12 version. Other than the submodule pythoncapi_compat.h, we maintain code that checks IS_PYPY

• implementation-specific details, like ctypes.__mro__, object identity vs. value-based equality, the whole elidation feature to optimize a + b + c, and PyTuple_GET_ITEM macros
• missing functionality like PyErr_FormatV
• refcounting differences like in np.resize() (it can be argued this is unreliable on CPython >= 3.14) and tracking accesses to mmap
• PyPy cannot modify tp_doc after PyType_Ready (it can be argued CPython should not allow this either)
• No support for limited-api on PyPy (nor on CPython3.14t)
• PyPy does not break complicated reference cycles involving both Python and c-extensions
• lack of sys.getsizeof on PyPy (and arguably this is inaccurate on CPython with a JIT)
• Different priority of sq_concat and nb_add when both are defined
• Some differences with __signature__ that may be cleaned up on 2.5, which does not support Python3.11
• Some typing stub differences

Should we remove some or all of the PyPy-specific work-arounds?