Mozilla browsers have long had an “easter egg” whereby if you enter about:mozilla into the location bar, you're presented with a nice quote from the Book of Mozilla.
What's queer, is that entering about:mozilla into Internet Explorer gives a blue page. No other about: address (that I've tried) does this.
Surely Microsoft aren't nicking source code?
Incidentally, why haven't Mozilla's copyright/trademark folks taken Microsoft to court over their use of “Mozilla” in IE's user agent string?