Hi Jeff,
I'm not totally sure about this - I've done it a few months ago- but my notes say:
1- just follow standard GIFT format
2- UTF-8 formating
3- The expressions concerning LaTex should:
- double $ symbol
- symbols ~ = # { } should have a backslash \
Not sure if it will help you but take a look. Also, I've only tried this with notepad files. Also, I believe ypu can find more useful information about this at Moodle docs.
https://docs.moodle.org/30/en/Using_TeX_Notation
Cheers,