Hi, I've been seeing this addon that shows the item's source many times and been wanting it for a long time, although I don't know the name of it and I've tried
WoW AtlasLoot: How To Enable Boss Levels | EarlyGame
Atlas Loot Classic - Addon for Classic WoW - 1.13.5
10 Must have Addons for Classic WoW 1.13 – Classic WoW Guides