The "MK8D Update N DLC [Softcobra.com].rar" file is a third-party archive providing the Mario Kart 8 Deluxe game updates and the full Booster Course Pass, including new characters and 48 additional tracks. It is primarily used to install or emulate the game's expansion content on PCs via emulators like Yuzu or Ryujinx, or on modded consoles, requiring a .rar extraction tool and proper file management to ensure compatibility.