In addition to the on-disc content, a Smashing Pumpkins DLC pack has already been set. Included in the DLC will be a brand new single called G.L.O.W. which will debut "exclusively in the game." Other older tracks come from differing Pumpkins eras, such as "The Everlasting Gaze" of early 2000 and "1979" of the late 90s. The three-song track pack will be available sometime after the game launches.
[Via press release]