@mkoeppe After these changes, how is one supposed to install ore_algebra with plain SageMath? I don't understand anything about the evolution of python packaging in the last 5–10 years, but I'm getting the impression that the requirements listed in pyproject.toml make pip pull passagemath-* packages from the internet even when one is trying to add ore_algebra to a normal Sage installation. In particular, it is not clear to me now how to install ore_algebra from a git checkout with no internet connection.

@mezzarobba One uses pip install --no-build-isolation for this use case. Then the build-system requirements declared in pyproject.toml are ignored, and the package is built against whatever is installed -- such as the monolithic Sage library.

Thank you!