German WW2 Auto Union Engine Type C1 - AUDI

Neat little engine. Would like to know its back story. German World War II engine made by Auto Union which would later become known as AUDI. Lot of interesting details including original Bosch spark plug. Has an engine oil measure under gas cap. Cloth air filter instead of oil bath. Locking spark plug wire boot. A mile long instruction list on top of gas tank and a fold up locking hand crank/ carrying handle. Likely powered a gen set.