This box can be an explosive of a Hexogen based Composite B
This pictures have been shown to 3 divers and explosive experts in Sweden and Germany. They all, irrespective of each other came to the same conclusion. The packet is most probably an explosive. The explosive must have been there during the sinking of the ship.
The white part in the bottom and right of the picture is the ramp. Top left show the port bulkhead where the box is mounted. I thick rope is covering a part of the bulkhead stuck around the box.
The closeup probably show the plastic explosive on a plating. The plating is metallic but is colored by reflextion from the explosive. The thick rope has winded itself around the explosive.
On later video recordings the explosive is gone. It was mounted just to the left of the welded hole at the bulkhead. The thick rope is still there, but moved some to the right.
The Green and Red X on the pictures below mark the place where the presumed explosive was mounted on the starboard side.