H shaped piece
"I asked if it was part of jackscrew assembly and told NO. see post 1315 from Sardak replying to me , pretty sure the guy works at A321 plant in usa
also look at these from Kulverstukas, I can't see a bit like the H, I asked because of course none of the images concerned are from same angle lighting etc."
Look at the structure on either side of the pivot points. They are airfoil ribs like you would see in a small plane's wing or tail. This shape exists on the APU air intake door, but is not part of anything on the jackscrew.
Look further down and closer to the camera, and duct box or air plenum is visible.