I tried to observe what I do when out on the bike today and I reckon that the closest I get to ankling is when the gradient increases and I go back on the saddle and push the pedals over the top of the stroke to maintain cadence, using a bit of ankle extension to do so - my knees are weaker than when I was younger and I rarely lift my arris off the saddle and honk nowadays - so as an alternative I go back on the saddle as described.
Otherwise, I reckon I might get an approximation of what ankling looks like but rather than being a result of extending the ankle for power, it is a case of relaxing the ankle and dipping the heel on the downstroke, letting the rest of the leg do the work.
Of course, my perception and analysis could be wrong and if I could see my technique from a third person perspective, I might have a different opinion.