Lemme 'splain - or at least try.

Sometimes, when all the factors are right, a sharp leading edge results in a spanwise bound (surface)vortex that sits just behind the leading edge. It's a small cylinder of air that sits there and spins, and deflects most of the oncoming air up and over it AS IF THE LEADING EDGE WERE ROUNDED. THat's why this wing behaves quite well.

I did some work on airfoils with sharp edges and steps in them when I was in school. Once took an Eppler airfoil, doubled the camber, then sliced the "top" of the airfoil off flat. It looked like an airfoil with a flattop hair cut. But it worked, quite well.