This is great and was a huge effort by Eric Snow and collaborators to make it happen.
To be clear, this is not "PEP 703 – Making the Global Interpreter Lock Optional in CPython", by Sam Gross. PEP 703 is more ambitious and add quite a bit of complexity to the CPython implementation. PEP 684 mostly cleans things up and encapsulates global state better. The most distruptive change is to allow immortal objects. I hope PEP 703 can go in too, even with the downsides (complexity, bit slower single threaded performance).
"PEP 703 – Making the Global Interpreter Lock Optional in CPython" (2023)
https://github.com/python/peps/blob/main/pep-0703.rst https://peps.python.org/pep-0703/
colesbury/nogil https://github.com/colesbury/nogil :
docker run -it nogil/python
docker run -it nogil/python-cuda