Those are the feet that go at the corners of the base. They allow some air flow under the base.
Good description!
All of us burn some of the insulation as wires get stacked up. If you burned all the way to the copper you can put some electrical tape on it to give it insulation. If you burned all the way through the copper, the wire needs replacing and your iron is way too hot. (That's a joke, well kind of. Not that funny.)