Wii Backup Disc

The Wii Backup Disc is a service disc apparently used inside Official Nintendo Repair shops to transfer personal data like savegames and console settings between Wiis as part of a repair.

It's not entirely clear what it does; something it does not do -- even though it appears it might -- is allow VC games to be transferred between consoles. Instead, it transfers the license so that the user can redownload the games from Wii Shop Channel for free.