dotOpacity

The same dot's visibility: on while it travels, off the moment it lands.

Two DiscreteDoubleKeyFrames in the template — one at nought and nought at 2.5 s — so this is a switch rather than a fade, and the millisecond before the switch is what makes it discrete here. Exported beside dotPath for the same reason: a still frame cannot show a thing that is only wrong for part of a cycle.