This file appears to be a pre-randomized Pokémon ROM hack packaged as a .cia file for direct installation on 3DS hardware.
You can typically find these files via the Ducumon website or their YouTube descriptions. Installation: Extract the .rar file using a tool like 7-Zip or WinRAR. Transfer the resulting .cia file to your 3DS SD card. Install it using the FBI homebrew application. ducumonikurandomizedcia-ducumon-rar
The terms in the string suggest a specific type of file often found in the handheld emulation community: This file appears to be a pre-randomized Pokémon
[Release/Help] Looking for information on Ducumon's Randomized CIA Packs? Body: ducumonikurandomizedcia-ducumon-rar