of course they could just guess the viewed position by tile requests. I guess the watcher is for some ‘social interaction’ thing later on. A while ago it was possible to enable the receiver part to follow the camera of other users, quite cool if one would ask to agree and select the person to share..

Yea quite nice effects.. you can see more details when appending &camera.zoomMax=22 to the url. Add &watcher.send=false to not send your current position to their tracker (check the numer of active websockets ;) The building models are made by their studio and it seems to be unlikely that they will share them independent from the map.