ZOOL!

Found this link inside userChrome-example.css in Mozilla’s profile directory:

http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul

Nothing shows up when you click it (for me anyway), but if you view source:

THERE IS NO DATA

THERE IS ONLY XUL.

Ha!

Also: Why does Moz1.3b have less popup blocking functionality than 1.21. Seems like now you can only block based on site, rather than requested/unrequested popups … 🙁