Damnit, I had looked for the details on that stuff. From the link in the first post I followed a daisy chain of sites that mostly quoted each other, and saw it called Thermawrap and Shelterwrap, which looked like brands, and aluminized structure wrap which didn't. I kept ending up with the stuff you insulate attics with to reflect infrared and give your A/C a break.
Then mrputter's post gave me hope, so I went to the link and ended up in another daisy chain but eventually I found it at Firezat. I grab a picture and the information, come back here and what's that? mrputter has a second link? Sure enough, it takes me directly to where I found the information.
I'm not a smart man.
Oh, along the way I
found this on fireproofing wood buildings with Sodium Silicate on Angelfire. Told you I was in a daisy chain, including the roots.
But
here it is, or at least one of them.
Looks like a heavy aluminum foil is glued to what's probably fiberglass cloth, then sewn together with Kevlar thread. Belt and suspenders.