The alphanumeric string 83w94F95r8V85E984945 is likely a hash or a randomized string. This is commonly used in:
: Bypassing file size limits imposed by mail providers. 83w94F95r8V85E984945.part3.rar
: Breaking a 10GB file into 2GB chunks to fit on FAT32 formatted drives. 83w94F95r8V85E984945.part3.rar
: Preventing automated systems from identifying the file's contents via filename keywords. 83w94F95r8V85E984945.part3.rar
: Most RAR files include a CRC (Cyclic Redundancy Check) to ensure no data was corrupted during the splitting or downloading process.