The superellipse or, more precisely (and way cuter), the Squircle. Since the reveal there’s already been a dozen templates or so that have tried their hand at the new form and I have yet to see an exact representation. This is one of those things that seem very simple, but is actually quite hard to get exact.
On the right you see what curvature continuity looks like. The curvature comb transition is a curve itself, starting from zero curvature. There’s no sudden break in curvature and, as a result, the highlight is smoother. This difference in curvature is harder to spot in an icon, but the important thing is that now the icons and the hardware are part of the same design language.
