Near as I can determine, the breast stroke frog kick and the diving “frog kick” are opposites. The breast stroke frog kick uses the back of the foot to push against the water, whereas the diving “frog kick” actually uses the top of the foot/fins for the push. That is the equivalent to what 50 so years ago we called the “whip kick.”
I disagree: in breaststroke kick the foot works as a propeller blade, there's little "push" component to the foot. Most "pushing" is the inside of the legs squeezing water out and back as the legs come together.
You can do modified frog pushing with the top of the fin, but you can also do it using foot rotation like in breaststroke and push with the "sole" side of the fins.