Rayman Pirate-Community

I was watching this video and noticed this user somehow programmed the scrapped first-person view back into Rayman 3 (GameCube version). Does anyone know how he did this or how to do it? Would it be possible to make an AR code or did he mod the game? Here is the video:

https://www.youtube.com/watch?v=pAsTbO28GXc&t=18s

i think that ribshark help him programmed the first person view