Conveyor (predictable URLs) 404 with a capitalised package name

[AA-Turner]

Describe the bug

The predictable URLs for Sphinx seem to have changed.

Capitalised URLs now return HTTP 404, whereas uncapitalised URLs allow downloading the source distribution:

• https://files.pythonhosted.org/packages/source/S/Sphinx/Sphinx-7.1.1.tar.gz
• https://files.pythonhosted.org/packages/source/s/sphinx/sphinx-7.1.1.tar.gz

This has caused our conda-forge build to fail, with error: RuntimeError: Could not download https://pypi.io/packages/source/S/Sphinx/Sphinx-7.1.1.tar.gz.

Expected behavior

Ideally, the capitalised version (& the lower-case version?) would enable downloading the source distribution.

To Reproduce

Follow the first link above (with capital 'S').

My Platform
N/A

Additional context

[di]

This might be a duplicate of #6?