The "story" behind this specific file is rooted in the history of the game's release and the digital preservation (or piracy) community:

: This is a file format used to install games and updates on a 3DS console using homebrew tools like FBI.

While the main story takes about to complete according to HowLongToBeat , this specific RAR file represents a era where fans bypassed official digital storefronts to preserve and play the game on their own terms.