The wife’s aunt found an interesting doodad in her house:
I was able to decipher the German myself. A Landrat is the district administrator, sort of the mayor of a county, and des Kreisses Euskirchen means the district of Euskirchen, which is on the border with Belgium. The hive mind helped me find out what this was, however.
I’m still left with a few puzzles. How was it attached to the licence plate? Who took it from the Landrat’s car? What was it doing in the house my wife’s grandfather built – he didn’t serve in the war and he certainly didn’t hoard Nazi goodies out of pride.