Very interesting. I have noticed more than one model Singer exlusive to German factories and developers. I have traced the first domestic zigzagger to be a Mundlos-Victoria introduced in 1920s. It was a few years before Pfaff, Singer, Bernina and other made theirs. There might be others who beat Mundlos to it, but not by much, so far I haven't found a trace of any.
On the industrial side of things, zigzaggers, overlockers, multi needle machines, setups with puncture cards / bands were in plenty decades earlier than the domestic version, and it's a bit hard to name an absolute first in the scheme of things.
Singer must have bought up one factory after the other over the years; they bought up Wheeler & Wilson, and produced their No 9 under the Singer name for a few years. Rumor has it that it was too much of a competition to model 66 at the time. Now every sewing company seems to have been bought and sold by Janome at some point.