First and foremost, some of the posts we see online will tell us that by using a mobile device and entering the code @[4:0] as a comment, you can find out whether your Facebook account has been hacked or not. According to the posts, you are totally safe from hacking if the comment transforms into ‘Mark Zuckerberg.’
https://www.elitereaders.com/4-0-mark-zuckerberg-facebook-comment-not-hacking-hoax/