Abel Kirui and Timothy Cheruiyot both heelstrike, they have a prominent forward lean and their legs reach forward to the point of overstriding. In addition Elijah Manangoi looks like he is almost overtstriding and has a forward lean.
I wonder if this is more efficient given that you are gaining ground when you overstride rather than relying on the push off of the ground.
Eliud Kipchoge reaches quite far forward and leans forward but pull his leg backwards before he overstrides.