: While standard Fortnite files are named pakchunk[Number]-WindowsClient.ucas , files with "SaturnClient" in the name are generated or modified by Saturn Swapper .
: The "Table of Contents" used by the game to find specific items within the .ucas . pakchunk20-SaturnClient.ucas
: This specific file likely contains the "swapped" visual data that allows you to see a different skin (e.g., a rare or unreleased outfit) in place of a basic one you already own. How it works technically pakchunk20-SaturnClient.ucas