When I look at games such as warcraft 3, or Diablo, or basically any games that contain items in them I notice that each item is unique. They all have different stats, different graphics, different names.

I took a wild guess that they don't use XML, although I know I might be wrong, but I just figured they use something that isn't easily human-editable to prevent casual hacking.

How is data such as item attributes stored in a game (2d or 3d, I suppose it works the same way in both)?