Everything a pointer and keyboard can do, with somewhere clear to do it. Each widget confirms what it received, so you can see the agent's action land - separately from the sky-blue cursor and ripples the extension paints on top.
Click once, twice, three times, or right-click. Each gesture is counted.
Give it focus and type. The text is echoed back below.
Drag from one side to the other; the start and end points are reported.
Scroll to the bottom to reach the marker.