Put together, refers to a specific, verified digital copy of the North American version of Mario Kart 64, stored in the raw, big-endian format.
You might wonder—why not just any ROM? The answer lies in .
If you have a file that fits the "mario kart 64 -u- .z64" description, you likely have the gold standard version of the game for emulation purposes.
Mario Kart 64 (U) [!] .z64 – correct endian for real hardware/flashcart