Coat of arms of Roßdorf in Kindberg

Coat of arms of Roßdorf near Darmstadt, Germany

On my urban walk through Kindberg I came across the coat of arms of Roßdorf, a place near Darmstadt in Germany. I love the dreamy moon in this city arms. Why is this coat of arms displayed in Kindberg? The simple answer is: Kindberg and Roßdorf are twinned.