Do you know about PHP easter eggs? I've encountered this often and it's actually pretty alarming - go to any PHP site and add this to the end of the URL
Do you see the PHP credits? If so then your PHP site is exposing sensitive information to your visitors. While the page itself may not contain anything harmful, a clever visitor could inspect what version of PHP you're running by looking at the headers and find a security flaw associated with that version.
It's good practice to always make sure
expose_php = off
is set in your php.ini file