LGTM

Should I cut a new release, i.e. would that make Sage packaging easier?

No need

Please make a new release (on PyPI too), as I just saw pip install fpyll (i.e. pulling version 0.6.0 from PyPI) and up to date python 3.10 venv with latest Cython, setuptools, etc, erroring out with

ModuleNotFoundError: No module named 'Cython'

Installing from master branch, i.e. pip install git+ssh://git@github.com/fplll/fpylll.git, worked.