Where does Mapbox obtain its buiding data?

[mcliquid]

@DaveF

Is this from their own edits or from another source?

AFAIK they are using the Microsoft Building Footprints, as they have announced here.

@DaveF

If Mapbox are creating their own building outlines, is there a reason it isn’t/can’t be added to OSM?

Check out the wiki here.