if the steganography signature is unique to the user receiving the content, then you might have to diff it with someone else's to see it (otherwise, you cannot

if the steganography signature is unique to the user receiving the content, then you might have to diff it with someone else's to see it (otherwise, you cannot really guess where the changes are which steganographically stores your identity). If it is the same content for all users receiving the text, then you can just retype the text (not copy/paste) into a different file. Of course, authenticity comes to question if you whistleblow by doing this.