OffKai Gen 2 is happening in the Hyatt Regency San Francisco Airport, 1333 Old Bayshore Hwy, Burlingame, CA 94010. This is a picture of the interior courtyard.
The numbering of rooms starts with the prefix 2000 (eg. 2001, 2002, etc) on the level above the conference rooms. The conference rooms are level with the top floor of that courtyard. I don't truly know what story it is on the exterior, but based on this it appears to me the photograph was taken from a room numbering in the 3000s.
I found a video of the courtyard from room 2028 that appears to be just a bit to the left and below the twitter photo. Based on this, I would presume the room is 3026 or 3030