The Wii U had a messy update system. A base game, version 1.1 update, and DLC were often three separate entities. WUA allows "repacking" these into one container. When you download a , you literally drag one file into Cemu and click play.
If you’re looking to preserve games you legally own, tools like (Wii U emulator) support extracting your own game dumps from original discs using a compatible optical drive. That’s the legal, safe method. wii u wua roms archive
In the early days of Cemu emulation, we dealt with formats—folders full of app files, often decrypted and prone to corruption or missing files. The Wii U had a messy update system