There is a strange handle (lever) on the left side of my new E-bike (Winora Youkatan 12 pro). It looks similar to the brake or gear shifter, and it is connected to the cable that goes somewhere (inside the frame). I tried to press it in various riding modes but the handle seems having no effect on brakes and gear shifting. This bicycle has 12 gears on the rear only, with the two relevant levers on the right.
What is the handle for? It is not documented in the user manual.