|Mario Kart Rush|
|Beta Name||Mario Kart RS|
|Beta System||Wii U|
Within the game's files is a file marked as bigbomb01. The file seems to be the Big Bomb Kart from Mario Kart 64's battle mode.
Another file found is called purpleghost09, when opened in a model viewer, the character that appears is Vivian, the ghost that appears in Paper Mario: The Thousand Year Door and Luigi's Mansion: Princess Business.
Lastly, there is a final file found in the game called scrtgreen??, which freezes the game when hacked on. However, if opened in a model viewer, the model appears to be a green ? Block, leading to speculation that the character data was never finished, and was scrapped early in development. Many fans speculate that this character would have been the character Link from The Legend of Zelda, although unconfirmed.
Hidden within the Mushroom Cup files, there is a special, fifth course name in the list. The name of the file is Mush4Birdo and, when opened, appears to be a large urban shopping area, with many signs of Birdo everywhere. Many fans have named this course Birdo City, Bowtown and, the most popular one, Shop Street.
In the file folders, along with MushCup00, FlowerCup00, Star001 and Special001, is a file labelled Berry002, being the only cup with the 002 file suffix. In the folder are six files: Berry1Sweets, Berry2Cave, Berry3Plains, Berry4Turtle, Berry4Laser and Berry2Dark. "Sweets" has been dubbed as Sweet Tooth, as it appears as a Sweet area, made of cookies, making it resemble GCN Cookie Land. "Cave" has been dubbed as Wii Caverns, as it resembles some of the underground courses from New Super Mario Bros. Wii. "Plains" has been dubbed as Flagpole Speedway, due to it having an extremely similar appearance to that of 3DS Piranha Plant Pipeway and the course Retro Hills, from Mario Kart Powers. The course appears as almost totally 8-bit, even having 8-bit Goombas walking around near the start. "Turtle" has been dubbed as Steady Forest, a damp forest area. "Laser" has been dubbed as Lazer Quest, as it appears as a Laser Tag-like arena. Finally, "Dark" has been dubbed Mysterious Wave, as it is a beach-like area near an Asian-like town, and during the night.
There is one known item that has been found in the files, that is questionitem88. The file is corrupted and will not open, though it is thought to be a ? Block.