You mean all the way back to when vehicles had drive shafts and exhaust systems that would use that hump area
Both my '12 and '13 seem to have some sort of
electronics under that hump, I can't believe they couldn't move it to somewhere else less obtrusive but personally it doesn't bother me too much where it is. IMO if someone is sitting in the back center seat(and I pity them

) they can easily straddle the hump with their feet, what bothers me more is the total waste of space around the rear shock towers. Apparently the shock tower themselves takes up
very little of how far out those bumps come out, now that I really object to. With both bumps coming out as far as they do it severely restricts how wide something can be in the cargo area. It's the reason I had to use our Prius(who's humps come out only a fraction of what the Leaf does) to haul home a relatively small flat screen TV, back of TV down.
Exactly what sort of
electronics is under that hump? It's probably the most secure area in the car for damage from an accident, I wonder if it's not maybe a HV connect or something that they really wanted to protect from accident damage.....