In general Kodak (and the US) actually lagged behind Europe where fine grain and extra/super fine grain developers were introduced much earlier. Hans Windisch published fine grain developers in 1938, Ilfords ID-44 was also pre WWII *and so Dk-20) and Johnsons Meritol based fine grain range had been available for a while. In the US it was Lowe and to a lesser extent Champlin who prompted research into fine grain developers.
Originally Posted by Michael R 1974
Kodak Ltd (UK) branded many products in the UKin the 30's & 40's, Kodesko, Kodatol (DK20) etc but seem to drop them after WWII. See page 3 of the 1944 Formulary.