It sounds like you're asking about a feature related to .wux files in The Legend of Zelda: Breath of the Wild (BotW), likely in the context of emulation (Cemu or similar).
Once converted, you can delete the original 25GB WUD file. botw wux file
To turn a WUX file into a playable mod folder, you use a tool called UWizard: It sounds like you're asking about a feature related to
Feature Title: BotW Legacy Archive Manager (Auto-WUA Converter) These may be binary or text
Not visually. He didn't see Death Mountain. He felt it—a distant pressure of heat and sulfur at the edge of perception. The floor under his boots seemed to slope toward an invisible river. The air smelled of pine and wet stone. A Guardian's targeting laser, unseen, made the hairs on his neck rise.
Types of BOTW WUX files
As research and analysis of the BOTW WUX file continue, we can expect to see new discoveries and insights emerge. Will we uncover hidden game modes, previously unknown characters, or clues about the game's sequel? The community's enthusiasm and dedication will undoubtedly lead to more exciting revelations about Breath of the Wild and its mysterious WUX file.
.wud file on a USB drive or SD card. This takes about 30-45 minutes..wud file to your PC.wux.exe with the following syntax:
wux.exe create -i "botw.wud" -o "botw.wux"
Alternatively, use Cemu (File → Load → select the WUD, then use the "Convert to WUX" option in the menu).