You're looking at StableBuild's Deleted PyPI mirror - where we index all deleted packages from the Python package registry.

passagemath-lcalc
10.5.30

This version was deleted from PyPI around 2025-08-21. Installing fails with:
$ pip3 install passagemath-lcalc==10.5.30 ERROR: Could not find a version that satisfies the requirement passagemath-lcalc==10.5.30