||.unr and .ut2
||Game maps or levels define the playing area
||Images put on to objects. Can wrap around 3D objects like a car wrap does.
||.umx and .ogg
||Music files such as theme music you hear in the background
||Various sounds of things like explosions, clicks, etc.
||.u, .int, and .ini
||Game engine files, configuration files are the core of the game server
||Object visuals mostly. See here for more detail.
||Little prefab animations like flames, weapon spawn sparkles, etc.