Just to offer a condensed version of mbrubeck's detailed information: Apple have played this strategically in the W3C so they could make this patent disclosure

Just to offer a condensed version of mbrubeck's detailed information: Apple have played this strategically in the W3C so they could make this patent disclosure as late as possible, despite the fact that they have been shipping these supposedly patented APIs in Safari since 2007 and encouraging developers to use them, and despite the fact that this proposed standard was first published back in May. The deadline was not sooner only because Apple strategically avoided joining the relevant working group, which would have forced an earlier disclosure.