Found here for Classic WoW: https://www.curseforge.com/wow/addons/oaks-loot-tooltips

Gives Loot priority Tooltips to Raid Drops for the "SelfPreservation Society" Guild on Skullflame.

The ["classPriority"] can be configured as well as an additional ["note"] in each raids relevant .lua file.

["classPriority"] will only show if it is not blank (e.g. ""), the ["note"] will only show if ["classPriority"] shows, but will also remain hidden if blank as well.

If the ["classPriority"] is changed to "NoteOnly" - only the note for the selected item will appear.