> extensions might need to [...] not depend on reaching into internals they shouldn't touch Is that the problem? I thought I read somewhere that the C/C++ exte

> extensions might need to [...] not depend on reaching into internals they shouldn't touch Is that the problem? I thought I read somewhere that the C/C++ extension API would have to be broken to allow for removing the GIL, for example. The API, not just internals that shouldn't be touched by user code. If it were only a rebuild, I don't think anyone would object; pip packages are built once per Python version anyway. Breaking the API would be a different story for libraries that make heavy use of C++ extensions.