[jlokier]

In this context, it's about scrolling when you slide your fingers along a trackpad surface.

It's supposed to be like "buttery smooth" scrolling on a smartphone. Whatever is on the screen should move with your fingers, with pixel accuracy and low delay, so it feels like you're dragging something around with your fingers.

When you let go, it might continue to scroll, as if you flicked the object with your fingers. This is called inertial scrolling. At the limits, it should show your attempt to scroll beyond the limits somehow. Apple and Android do this differently for patent reasons.

Of course with a touchpad the image isn't underneath your fingers like with a smartphone. So the scrolling amount doesn't have to be the same physical length as your finger movement. It's scaled, but it should feel similar to smartphone scrolling.

There's no arrow.