The collection contains 490,000 tracks, allegedly gathered by an anonymous academic group that grabbed around 1.3 terabytes of music from the site to study between 2008 and 2010. While this represents a pretty small percentage of the total tracks lost -- estimated to be around 53 million -- many users are nonetheless delighted by this haul. Jason Scott from The Internet Archives tweeted that one creator managed to locate a track they'd assumed for was lost for good, while Twitter user @pinkpushpop found a bunch of early clips from the likes of Katy Perry, Nicki Minaj and Donald Glover.
You can investigate the collection using Hobbit, the search and playing mechanism for the Dragon Hoard, although The Internet Archive notes that the index will take a little while to initialize when you first load it. It also says that the collection "can best be described as unwieldy", so who knows what gems of bygone internet nostalgia you'll find there.