I'm surprised this targets TeX rather than lilypond, which AFAIK is the gold standard for free (as in beer and speech) music engraving.

I checked, and lilypond also offers features for Gregorian chant notation [1]. Has anyone used both and is able to compare?

[1] https://lilypond.org/doc/v2.25/Documentation/notation/typese...

I may be one of the few HN users for whom this is an extremely useful resource. I’m an Anglican priest, so I’m often scanning and pasting bits and pieces of chant into our bulletins. This will, I hope, allow me to create much cleaner looking chant texts in the future! Thank you for sharing it!