Files have had the encryption removed. They can be installed directly onto a custom firmware console (via FBI) or loaded directly into emulators like Citra.
Navigate to your installed titles and locate the Pokémon X update. pokemon x update 15 decrypted 3ds eur usa
Launch Citra, Lime3DS, or your preferred 3DS emulator. Access the Installer: Click on File in the top menu bar. Files have had the encryption removed