Phpb8b5f2a0 3c92 11d3 A3a9 4c7b08c10000. This information may be useful to an attacker in determining the software versions installed. A list of credits for php, defined by php_credits_guid.
W3af has a number of discovery plugins for gaining information about a remote server. I tried to turn it off from php.ini with expose_php = off but it still comes up in the scan.