The file you are referring to, GROOVE COASTER WAI WAI PARTY (NSP)(32 DLCs).rar , is an unofficial package typically found on piracy or emulation sites like NxBrew for use with Nintendo Switch emulators such as Yuzu. It contains the base rhythm game along with a collection of its many downloadable content (DLC) packs. Game and DLC Overview
To use an .NSP file legally on a PC, you must own a physical or digital copy of the game and "dump" it from your own Nintendo Switch console. GROOVE COASTER WAI WAI PARTY (NSP)(32 DLCs).rar
Remixes and original arrangements of Touhou tracks. The file you are referring to, GROOVE COASTER
Individual DLC packs are sold for $15.99 each on the Nintendo eShop. Emulation and Legality Remixes and original arrangements of Touhou tracks
Featuring popular tracks from various Vocaloid producers.
Music from other rhythm games like Chunithm and Undertale.