Hi! For the legal aspect the other comments have already answered with loads of details (thanks!).

But to answer your question more precisely, this game uses the CIC chip alternative made by Infinite NES lives: http://www.infiniteneslives.com/snessupplies.php

This is one of the several CIC alternatives available, including the most popular that is the open-source SuperCIC chip: https://sd2snes.de/blog/cool-stuff/supercic