The drawings were done by Bosnian designer Kemal Curi? and were posted as part of an interview with him about the 2015 Mustang.
A look at the sketches shows many of the styling elements that made it into production, from the slim headlights to the fastback to the tri-bar taillights. The production version seems to have lost some of the aggressiveness of the earlier sketches, although that’s to be expected.