I think that's just the structure of the nose gear well with the aerodynamic fairing removed. Given that the missing fairing seems to be fairly permanent, it might be a non-flying aircraft for handling or maintenance training, perhaps?
Edit: I see it's marked "404 CLSS," a USAF Combat Logistics Support Squadron. They do things like combat repair of battle-damaged aircraft. Possibly they were using this airframe as a mule to practice repair techniques. That would jibe with the missing canopy, absent engine covers, and other missing bits (the joint between the horizontal and vertical stabilizer seems to be missing something too).