As single-braid construction, the rope is expanded to run the shock cord inside it. Very clever idea. When the shock cord is in its normal state the rope will look puckered and wider diameter. When it stretches out, the rope will constrict and the shock cord will stretch. At some point the rope would take up the whole load if it reaches its uncompressed state equal to the diameter of the shock cord, or if the shock cord breaks.

You'd use a thinner shock cord and thicker rope than you would if either were sized independently, to allow for them to work together, because the shock cord would become the rope core... Maybe 1/4 or 5/16" shock cord with 3/8 or 1/2" rope.