The HPy project has been
around for more than a year now; it is meant to provide an alternate C API
for Python that allows extensions to the language to run, and run well, in more
environments. It first came to our attention in a report
of a talk at the 2020
Python Language Summit (LWN coverage), but it goes back to some discussions that were
held at EuroPython 2019. There
are a number of ways that the existing C API holds back innovation for
Python, but there are also some hugely important extensions (e.g. NumPy) that use it; any change to the API
needs to take those into account.

Source: LWN.net – [$] HPy: a better C API for Python?