"PKA" is an abbreviated release tag used by scene groups or internet uploaders to claim credit for ripping and uploading the game online.
The .part2.rar extension indicates that this is the second piece of a split WinRAR archive.
You cannot extract this file by itself. You must have all sequential parts (Part 1, Part 2, Part 3, etc.) downloaded in the exact same folder to successfully extract the full game. 🎮 Nintendo Switch Cartridge Image (XCI)