... have been on my mind since I first saw them back in 1993 (mental eh!) but I was too caught up with my 1/8th Tiger II build at the time.
OK time for some speculation; I have the idea that these held a two man handsaw ("Drumsäge" in German). Jagdtiger was a huge vehicle and they needed to hide it with branches or the like. This is what the brackets look like;
As you can see bracket marked 1 is for something quite thin to be stored while bracket 2 is flat and the metal strip of the bracket is missing. The set up of the brackets seem to match the size of the two man handsaw.
What made me think of this handsaw was "X2" at Iserlohn. Here´s a closer look at the "X2";
Now "X2" has extra long bolts (see arrows) on the inside of the exhaust armoured covers indicating that it had the towing device at some time but was removed. This would mean it was a very late version (= Kubinka) and what´s on the engine deck - a "Drumsäge".
What do you think?