This is "standard"
Starthilfe (rocket pod with parachute), i.e. Walter 109-500 rocket engine or commonly known as JATO pod in the post war years. Fittable to all Ju 88 A´s, eliminating the need for Ju 88 A-2 (that subsequently was cancelled variant). Must common useage by Ju 88´s was by the heavily laden Torpedo Bombers.
https://en.wikipedia.org/wiki/Walter_HWK_109-500
-Ed