Help with particular Gamecube file format...

So I was digging through the files on a Gamecube disc (Tony Hawk's American Wasteland), and one file extension in particular caught my eye:

".ngc"

The strangest thing about it is that it comes after another extension on nearly every file on the disc: "loadscrn.img.ngc"
"shark.tex.ngc"

Is it some sort of compression thing? Does anyone know of this in another game?

 

Well, for embedded systems such as the Game Cube a file extension is a arbitrary combination of three ASCII characters which has no particular meaning.

So on this context .NGC files can be anything. It really depends more on what the programmer wanted to make his program work like than anything else.

By this I mean I could make a game and name all files anything I wanted, but as long the main game executable knows the name that refers to each chunk of data, it can read them correctly.

I'd say you open them on some hex editor and look inside.