This is the second piece of a "split archive." Modders often split large map files into multiple parts to make them easier to upload and download. How to Install Multi-Part RAR Files
Since this is "Part 2," If you try to extract just this file, you will likely get an error saying "Unexpected end of archive." Step 1: Gather All Parts GF301122-ETS2-1.46.2.2-ELA.part2.rar
This indicates the specific version of Euro Truck Simulator 2 the mod was designed for. This is the second piece of a "split archive