Drive around town in "D" or "3" for MGP?

[arose62]

I'm quite impressed by how smart my 2013 Yaris automatic transmission is - if I'm going downhill, and leave my foot really, really lightly on the accelerator, the fuel consumption drops to less than 1.0 l/100km, if I take my foot completely off the accelerator above 70km/h, the consumption drops to 0, and the car gradually slows under engine braking,

What I've recently noticed is that under 70km/h, if I take my foot off the accelerator completely, slight engine braking happens, with low (but not zero) fuel consumption (as if the car knows I want it to keep rolling).

But, if I tap the brake pedal, the fuel consumption drops to 0, and more significant engine braking happens. So, if I'm approaching red lights, I lift off the accelerator, tap the brake, and coast to a stop using zero fuel, whereas if I *don't* tap the brakes, I still coast to a stop, but more gradually, and using (slightly) more fuel.

These behaviours don't seem to be documented anywhere in the owners' manual.

Cheers,
Andrew