Just load it up on NTR and you can see the codes, you don't even have to load up the correct game as long as the folder you put it in matches the game's! But almost every place you can find plugins has a detailed list of what cheats there are, so what's the point bothering to look into the file?
But just to answer your question, any hex editor can at least look into SOME plugin files (depends on many things like what version they use and whatnot), just not edit them (they get corrupted), with a lot of data being garbled up, but the cheat names at least are visible (but like I said, that's only in SOME plugins).