What some people will do for experimentation.  I think they literally destroyed the looks of what I thought was one beautiful plane.   The picture is courtesy of  Plane-A-Day.   

They were doing experimentation leading up to the X-1.  They wanted to make sure that a plane with supersonic-capable airfoils and a swept-back wing would be controllable in subsonic flight -- so, they modified an existing fighter.

Note the constant-diameter plug just aft of the wing -- that's because they swept the wings back, then realized that they'd have CG problems.

 Looks like the NACA Mustang in the background.

  It looks like the fueselage plug also changed the incidence of the stab, they have what looks like a pair of jack screws sticking up at the leading edge at the stab / fin intersection. They maybe ground adjustable, or motor driven to preset limts for various flight profiles, hmmmmm.....

What you are seeing is a pair of 16mm movie cameras used to look at the wings when they were tufted for air flow studies. There were also a pair of 35mm cameras on top of the canopy structure.