I just got my parts back from the plater, and it time to start welding again. For this, I need to get back to my question; the metal tab and its purpose.
The answers you guys gave me ("to support the wooden floor boards") satisfied me for some time, but now that I have everything clean and in pieces, I can 'Lego' it out and the 'floorboard' answer doesn't seem correct. It is simply 12 mm (1/2 inch) too low to carry the floorboard : the bumper reinforcement already has a flat surface in the middle that supports the wooden plates and that reinforcement is just 2 inches next to it. (The 2 special prongs pointing upwards grip the vertical trim panel around the rear lights.)
The metal tab also is not purposely added to act as a cable harness clamp, as these are generally different in the car (the omega shaped thingies). One of these dedicated wire harness tabs was just 2 inches next to the metal tab. So, holding the harness seems not to be its function.
The only thing I can guess is that it hold the foot end of the jack, to prevent it from denting the rear valance. Is that what it is supposed to do?
I've made some (a lot... ) of pics to help explain what I have.
I'd like to ask a second opinion if I may.
Regards,