"Wow... can I do whatever I want with this stuff?
NO. Bungie still holds the copyrights to these files. They're allowing them to be distributed for free (mostly because you can't buy them any more) - but they're still Bungie's intellectual property. You can't, for example, sell them."
Has anyone seen a clear statement, since the "freeing" of Marathon, that the copyright holder for the game is "Bungie Somethingsomething, Inc." or "Bungie, a division of Microsoft"?
I poked around on the Trilogy release page but didn't see anything definitive.