"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Banners Begin Going Up at Yerba Buena for iPad 3 Media Event
The banners are typically tied into the graphics found on the event invitations, but it is not yet evident what the final image for this event will be once crews have completed their work.
Update: The banner is almost complete, with the large white apple logo in the middle of what appears to be a vibrant splash of paint.
Thanks to Resolve Digital developer David Jones (@d_jones)