@sonny12681
At the time this was released, RPG Maker MV had updated. Because of this older files made with older versions of the generator, weren't able to be opened by this new generator. And thus if you updated the editor, you couldn't use your old generator files. Thus this video showed you how to make your old generator files work with the updated generator.
Also note that editing the generator files won't make your game not work, you'll just be unable to use the generator.
As well as, I do know basic coding so I have and do edit the base code, usually thru private, personal plugins but I still do. And yes I've made videos from time to time displaying and doing that but I don't release videos with code, I haven't test with or played around with, I make sure that the code I give out works at the time I'm using it and I strive to make that clear for my audiences.