There is only 2 ways an extension is distributed to people in the Python universe: As a SOURCE CODE distribution OR a COMPILED BINARY distribution. Wheels are generally the "compiled" distribution, these are also generally built for a specific runtime + python version. For Python 3.10 wheels, these would already be compiled against the precompiled header. For source distributions, they require "building" before being deployed, for Python 3.10, this will include the precompiled header. I'm aiming at least to not increase the API overhead for when invoking stuff like "Py_TYPE", "Py_INCREF", "Py_DECREF", etc. Py_INCREF and Py_DECREF are the worst offenders as they are generally HIGHLY INVOKED functions and are also the functions that are ALWAYS INLINE OPTIMIZED away by modern compilers.