Thanks to djidji for pointing this out in this thread on the macosxhints OS X Developers Forum. It’s completely useless, but it is April 1st, so it seems fitting to publish it here today!
The php developers have a small April Fool’s Day Easter egg hidden in the PHP code. If you have PHP enabled and working, just create a small PHP file that contains the standard “show install information” PHP command:
Load this file in your browser, and check out the new PHP logo. You’ll only see this, of course, as long as your system shows the date as April 1st.