I got this movement from Eugene Teo. He had no name for them so this is what they ended up being called. And for good reason. There's a ton of cool things going on with these that make them an awesome ham and glute movement.
To start, get the toes in a pronated (pointed out) position which means you've got some external hip rotation going on. This is a requirement for a full glute contraction.
Next, you've got to keep an isometric contraction in the glutes virtually the whole time because you're having to execute hip extension into the bench to hold yourself there. Remember, the toes are pronated, and we've got isometric hip extension. That means bad-ass glute contractions.
We've also got the hamstrings working under constant tension at every inch of every rep because the knees stay in a position of flexion. And with the feet pushing into the bar, the hams literally get no break. That means a metric butt-ton of metabolites in there for each and every rep of every set performed.
Do 4 sets and as many reps as possible each time you train low body. Try to beat the total number of reps you can do each and every workout.