"Andrew Chaplin" wrote

Is that a thrust reverser?

It must be. I suppose you noticed the slots on the sides of the tail, and
the bottom. Once that flap inside the tail cone comes down all the way, and
two more on the bottom come up, that would effectively block the rearward
exhaust flow, and send the flow backwards out the slots on the sides and
bottoms.

Pretty clever. Those slots also probably help cool the exhaust gas
temperatures during regular flight seen by enemy infrared seekers, too.
--
Jim in NC