Probably Gamehacking if I'm not mistaken, which is why a lot of codes for the same thing are listed multiple times. The site has the built in ability to convert saves between formats and download them as a list.
A lot of them are RAM codes that cannot be converted to ROM codes, and AFAIK the console doesn't support RAM codes. You'll also see a lot of codes where you change digits to a certain variable (play as character X, start on level X) and those codes are useless where you can't edit them on the fly.