These are files to enhance the microtonal support in LilyPond,
incuding Sagittal notations in LilyPond.
It probably came from http://x31eq.com/lilypond/ or

The Sagittal font and musical examples were provided by
Dave Keenan and George Secor.
There's some kind of license on them.
The code to implement the example is mine.
Everything else you can do what you like with.

regular.ly -- Standard file for JI retuning, used by the Athenian and
Promethean implementations.

addmts.py, addmts.py3 -- Retune output MIDI files to use the
MIDI Tuning Standard

Sagittal2.0d10.otf -- the Sagittal font.  Check for the latest at

sagittal.ly -- support code for the Sagittal glyphs.  Generated by the Python
file make_sagittal_ly.py

athenian.ly -- support for just intonation with Athenian EDA accidentals.

promethean.ly -- more precise accidentals than Athenian

ji12.ly -- just intonation written as 12 note equal temperament.
    (This makes sense when used with cents.)

sagji.ly -- common code for Sagittal with just intonation

trojan72.ly -- just intonation rounded off to 72-EDO

trojan60.ly -- Just intonation rounded off to 60-EDO

trojan.ly -- common code for Trojan notations of JI

ratios.ly -- Example of JI duplicating the Sagittal paper.  Output in
ratios.pdf and ratios.midi

fig6.ly -- another example