[Kirathis]

Hmm, I actually think it does look like one of the aforementioned window boxes. The top left corner looks like a separation between the box and the cover flap. Just looked at a couple of the other set boxes and they all look like that. Nearly flush with the front but with a small corner on the top left where you can see the white backing of the board. I also agree with Jeddostle that there is a Hasbro logo in the bottom right corner. Whether this is legit or a mock-up remains to be seen but I would say it looks like a taller version of some of the boxes we have received for exclusive sets over the last couple of years.