WishList
The purpose of the addon is:
You can put items on your personal wishlist and it notifies you if you loot it. Cross character, and even if grouped and someone else loots it.
But it also got a search tab where you can search all ingame sets, there locations and other information like set bonus by text.
Basically the data of the sets is stored in the library LibSets and WishList provides the search UI for it.