This is a personal project but I decided to publish in case others find it useful, this is kind of a placeholder addon for any extra tooltip lines, but right now all it adds is a check of conduits you already have learned, and will show either "Unlearned" or the item level you already have learned. This makes it much easier when browsing world quests or the dungeon journal to see what you already have. Since this is the only behavior of the addon I don't have any kind of configuration or anything added, maybe that will get added later.
The ilvl text will be red when the item is unlearned or when you know a lower level already, blue when you know the same level, and green when you already know a higher level.