I suspect it’s an IR broiler/salamander with a ceramic element that gas and air are blown through, and combustion occurs without a visible flame. Such elements were introduced by Corning Glassworks at the World’s Fair in NYC where Restaurant Associates had a fine-dining restaurant (I can’t place the year, I’m sorry). Such elements are currently used by DCS (Dynamic Cooking Systems) in their ovens and BBQs, and I just saw a review in Consumer Reports and Cooks Illustrated of a BBQ that uses these elements exclusively. The BBQ did quite well in CR, but at the bottom of the pack in CI, and I have to say that the critcisms CI leveled at it weren’t on the mark, as far as I could see; for someone who wants a BBQ that can sear and crust meat beautifully, this particular model seemed to do a great job. I suspect it makes a crappy oven replacement for roasting a turkey; that’s what smokers are for, anyway.