Would I be correct in calling that joint a "mortise & tenon" just trying to remember the Norm and the New Yankee Workshop.
It's a type of mortise and tenon joint, but it's a specialized one for rail and stile joints. Like Karl said, it's done on a purpose built machine and there's really not much skill involved.
I can't believe nobody's commented on the pocket screws holding it together from the inside. You can see the holes for them on the underside of the lids. That's a slick trick for no visible fasteners on the outside.
