Just a guess from watching the video a couple of times - But to me - it looks like the winch or linear actuator they are using is attached to the outside top of the 'latch'. when pulled it centers & then raises. when released it swings back into the lock position.
Might want to send the youtube owner a message & see if they will give instructions?
Wow... I tracked down their site after posting a re: on the vid.. That's a pretty simplistic method.. Basically what I had in mind, but just haven't had the time to work out the wiring on.. Bookmarked and planned to implement.
Though I'll just use a bare motor.. I have an old Kyosho RC car motor laying around that I used in an e-heli I built that's not seen service in some time.. Will have to build something up with it.