It sounds like you’re referring to a compressed file for , which was originally released in 2009.

: The main story takes about 8 hours to complete, but if you want to explore everything Pandora offers, it can take up to 17.5 hours .

: The game serves as a prequel to the 2009 film, set two years before the movie's events. You play as a signals specialist named Able Ryder and eventually choose between siding with the RDA (humans) or the Na'vi.