This is a file extension for Nintendo Switch packages. It is the format used by the official Nintendo eShop for digital games. Atualização (Update):
Originally on the N64, now updated from its native resolution to a sharper . It retains the classic 4:3 aspect ratio.
If you're looking to update the game, ensure you're using official channels like the Nintendo eShop to avoid any potential issues with NSP files or ROMs.