if (strtolower($_SERVER['HTTP_USER_AGENT']) == 'hacker')
fatal_error('Sound the alarm! It\'s a hacker! Close the castle gates!!', false);
...
:o
That's an old (2005) easter egg. :P
Intended for what?
An easter egg is an easter egg...
Uhm. Now that's eggy. I doubt it is.
Hidden part in the software intended to cause humour or nostalgia. It's a hidden egg.