That's an empty connector on most of our cars. It was used for a car-telephone hook-up.
That white powdery looking stuff on the immobilizer board is corrosion from being wet. You may get most of the function back if you can clean it off and dry it. Usually people clean them with alcohol and a soft brush. Even if you can get it functional, some of the corrosion will likely continue on the internal components and kill it later.
The best repair is to have the data transferred to an undamaged unit.