At a friends house. He recently cleaned out his mother’s home and found this really great looking cast iron Dutch oven. What is the insert for? Google, in this instance, has not been my friend. I’m finding that it’s called a “trivet tray rack,” but that’s about it. The rack is no more than an eighth of an inch thick. If you look closely, you’ll see three little knobs on the underside that hold the trivet no more than a quarter inch off the floor of the pot. Anyone know? Anyone want to guess?