Note: Under U.S. law (DMCA 1201), circumventing Wii disc protection or distributing game backups is illegal unless you are making an archival copy of a game you personally own. Do not download copyrighted game files from unofficial sources.
For those looking to actually use this file type, here is a step-by-step overview of the process, from conversion to play. mario party 8 wii ntscwbfs exclusive