Ex 23 breaking bytes?

I don’t get how to break the bytes. My reading of that means to corrupt it so instead of for example it storing Afrikaans it stores Afrikbbns or something like that. Am I on the right lines? Any explanation would be greatly appreciated.

One way is to take something encoded in say, koi-8 or Big-5 and put it at the end of the file or the beginning. Then it’ll complain.