At least I suspect it is, painted here on the inside of a small wooden hut for hikers nestled deep within the Schwabian Alb:
The Thirty Years’ War (Dreissigjähriger Krieg, in German) lasted from 1618 to 1648. If you look closely at the coats of arms, you’ll see Baden on the left, and Württemberg on the right:
But to be honest, this is just a semi-educated guess. If you have any better info, do let me know!