Not all auto glass is laminated.

For most cars only the windshield is laminated. This consists of two pieces of glass with a plastic "glue" layer between the two. This helps keep objects from entering the passenger compartment. It also tends to keep the glass sort of intact preventing large shards from flying around.

On MB cars, the rearmost glass tends to be laminated in the same fashion as the windshield.

All curved side glass is tempered, some flat side glass is laminated like a windshield but that is limited to 50's cars and trucks. Tempered glass turns into rock salt sized pieces when broken, this is because of the high internal stress when the glass is made causes it to shatter in all directions not just crack . It is a lot harder to break side glass than you think though a sharp edged tool does wonders. I have had tempered glass explode a few times. A car going from 10 *F into a 70* F shop had the rear window explode, and a couple of side windows break without any external impact.

I don't know where the metal in the middle came from other than the rear defroster wires may be there. As for breakage due to heat, you could look around here www.tintdude.com When getting tint film to shrink to size requires a heat gun, this might cause laminated to crack.