Hi Matthias Are you sure that cython 3.0.x is required for Python 3.12?
The changelog from cython 0.29.36-1 has:
* New upstream release.
- Includes Python 3.12 support (Closes: #1004725)
and upstream's changelog [1] mentions Python 3.12 a couple of times.
Please also see my message [2] in #1028157.
Regards
Graham
[1] https://github.com/cython/cython/blob/0.29.x/CHANGES.rst
[2] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1028157#67
