If you are looking for specific data within the game's root (which would be contained within a WAD if installed as a channel), the NSMBW Modding Database provides a detailed map of the filesystem: : Contains all level and tileset files. /Object : Houses the game's 3D models. /Sound : Stores music tracks and the BRSAR audio archive.
While the game is no longer officially available for purchase, gamers can still experience New Super Mario Bros Wii WAD through various means: new super mario bros wii wad
, particularly in World 9, which requires "perfect" timing and speedrunning skills. If you are looking for specific data within