[vector_spaces]

PyPy is a JIT-compiled implementation of a language called RPython which is a restricted subset of Python. It does not and has never attempted to implement Python or replace your CPython interpreter for most intents and purposes. CPython is the official reference implementation of the Python language and what you probably use if you write Python code and don't understand the difference between a programming language and its implementations (which is fine)

[saila]

This doesn't sound right. PyPy has always been described as an alternative implementation of Python that could in some cases be a drop-in replacement for CPython (AKA standard Python) that could speed up production workloads. Underneath that is the RPython toolchain, but that's not what most people are talking about when they talk about PyPy.

[cfbolztereick]

Exactly correct. PyPy is a replacement for CPython 3.11, which aims to be fully compatible with pure Python code (C extensions are a more complicated story).