On further inspection that is a pretty elaborate “self-latching” mechanism.
It appears that one has to “push in” on that spring loaded plunger to pull
the drawer open via the “teardrop” handle.
I don’t think they were made for use on a door because they can only be installed at the “top” edge. Of course they could be installed on the door of a base cabinet.
Anyway, maybe they were made for use on a boat or ship’s cabinetry to insure they don’t “open” due to the “rocking of the boat”.