I've been searching throughout my LU files for a while now, to find out where I can find the game music and the LDD models used in game. (if it helps, I still only have the Beta version) I believe that somewhere within the files there is a list of websites that the game gets the excess stuff from. If anyone has any help or information, I need it! If you have the exact location of these files, I would love to know.

I'm not sure if LU gets any of those types of files from a server (they store minifig info and that sort of stuff) but with the current version, out of the 11.4 GBs that LU stores on your computer 9.47 are stored in the pack folder, which contains PK files. These are unreadable unless you use special software, there is a program someone wrote specifically to open these but it goes against the TOS and you are unlikely to be able to find a copy (I have opened a few with the Notepad program, but most are so large they freeze the program.

First off, if you've opened the Patcher to let it Patch recently, then you have the current files. The Beta version is the exact same as the one everyone has now.

Secondly, the .pk files do in fact contain the needed components of the game, and extracting those is against the TOS. (As mentioned above.) I've figured out that the game files are downloaded as compressed .sd0 files, which the Patcher unzips and somehow rezips into the .pk files. Quite fascinating really, and if you keep an eye on the versions folder you can notice a few pop up.

The files in the .pk files (in theory) are uncompressed automatically when playing the game, as needed, so it's a win-win situation - the files are hidden yet they can still be quickly loaded wherever they are needed.

Another way, though used less often, is online storage. If something goes wrong with any of your files (or if they're out of date) the server automatically finds and corrects the problem by temporarily loading the necessary components for a one-shot use.

Though most correctly state that there is 11.4 GB or so of files, the entire game actually takes up over 20 GB, though apparently it only downloads if you encounter a bug with the Patcher. It's a weird one, I still haven't figured out why it happens... or why no one else seems to know about it.

EDIT: I should have mentioned - the files are located at cache.legouniverse.com, but do NOT try looking around there. I and a few others found out from a Dev that it's not very good to do so, and you could get in trouble. That's where they come from, nonetheless.