: The "de3" (part 1 of 3) indicates this is a split archive. You will likely need to download all three parts (e.g., Cargo Pack 1 de3.part1.rar , part2.rar , etc.) to the same folder before you can successfully extract them.
The file is typically associated with modification (mod) packs for simulation games, most commonly Euro Truck Simulator 2 (ETS2) or American Truck Simulator (ATS) . These "Cargo Packs" generally contain new trailer types, heavier loads, or specialized cargo to expand the variety of jobs available in the game. Important Safety Information Download File Cargo Pack 1 de3.rar
: Launch the game, open the Mod Manager , and enable the cargo pack. : The "de3" (part 1 of 3) indicates this is a split archive