What are the characters allowed in note names?

[matj1]

“A#” works as a note name. “ř£” doesn't work as a note name according to my testing because LSDJ says “ROM...FAIL! TRY CLEANING PINS OR FLASH AGAIN.” with that note name.

So the limit is somewhere between them. I don't know what the character encoding in LSDJ is. I would like to have it documented somewhere.