Ah, thanks! I can see it in these frame grabs:
The above shows its rough position and size (unfortunately mostly obscured by the gentleman in the foreground), and the below shows it in position:
It looks to me that the cool air is cooling a lot more than "just the electronics" (I can't find that reference in a hurry).
It goes to show that a decent thermal management system doesn't have to take up a whole lot of space, or be particularly expensive or difficult to work into the design.
Please, someone, design a retrofit for various Leaf batteries! Though I can imagine that a retro-fit would be a lot harder than designing from scratch. Maybe whole e-NV200 packs can be fitted to Leafs with some effort? One problem would be supply; there must be (wild guess) 10:1 Leafs to e-NV200s.
[ Edit: Please pardon the quality of the frame grabs; I didn't realise it was at 480p quality till after I grabbed and uploaded the frames. ]
2012 Leaf with new battery May 2019. New to me June 2019.