: You do not need to purchase the software separately; it is a free download intended for use with the physical Mario or Luigi kart sets.

: A physical RC kart (Mario or Luigi) is required to actually play the game, as the software uses the kart's built-in camera to create the augmented reality track in your home. Mario Kart Live: Home Circuit NSP/ XCI ROM v2.0.0 Download

While this specific string is often associated with ROM distribution sites and homebrew communities, it is important to note that the official game software is actually on the Nintendo eShop . Game & Update Details