Is cargo capacity........

Yes numbers are for Gen3 2010 to 2015.
These are really the last time we got some decent volume numbers.

As fine point, the video never really explains how EPA cargo volume 21-ft3 makes sense. The video says for Gen3 Toyota added 3-ft3 more total interior space, but then cargo space went from 16 to 21-ft-3, which fairly obviously relates to a change in reporting method to "EPA Cargo Volume" for Gen3.

So be careful to realize cargo space numbers are whacky we do not totally undertsand it. But Gen3 is the king of Prius Liftback Cargo Space, I'd say. You got add'l 3 ft3 under the floor and you still get a spare tire. Lots of room back there.

Obviously we have discrepancy EU method (15.7-ft3) which may be conservative (box loading technique leave gaps), and EPA Cargo Space (21+ft3) which may be off for liftbacks, but nobody is talking so we are stuck not quite understanding it all.