Majority of it was put together on public records. The funding was all public (majority of it) and around specific times it shows a dramatic drop of funding being supplied to specific accounts (accounts connected to bungie and other things that funded destiny) and public employment records showing that withing a week of the lead story writer leaving it showed many of the employees also quitting shortly after. Obviously some of it is portioned with speculation but after many rumors started floating around the parts of speculation now being used mixed with the facts make the most sense. Not to mention when bungie is asked questions related to this speculation its never denied just avoided.