In emulation naming conventions, (U) stands for USA/Ultimate region. This is the key to the essay's likely thesis.
: This is a specific naming convention used in emulation circles to denote a Wii or GameCube disc image meant for United States consoles. SUPER MARIO GALAXY 2 ROM-U
If you already own Super Mario Galaxy 2 on the Wii, sourcing a ROM-U online is a legal gray area—but it is functionally identical to making your own backup. If you do not own the game, you are pirating it. This article exists for educational and preservation purposes; support the developers by buying used copies or purchasing Super Mario 3D All-Stars (which, ironically, does not include Galaxy 2). In emulation naming conventions, (U) stands for USA/Ultimate