Hmmm... not sure.
But this page was embedded inside an page (removed after exposure) on buildwindows.com as iframe.
And the page was streaming a backstage testing video from the BUILD conference.
short clip of that video:
and some snapshots: http://minus.com/mblXtgr9mz
They change the testing video stream to an old Office 365 recording, just for testing IMHO.
But of course, it could be changed anytime by MSFT, so, just focus on buildwindows.com and PressPass