This may be a simple answer, but I've always wondered how in the middle of a war soldiers would know the names of equipment of their enemies. Taking WW2 for example, how did they know that the MG-42's were actually called that by the Germans? Was it from POWs? Or did the Germans publish the names of their equipment in literature that the Western powers could get access to?
u/kieslowskifan has an answer to this!
https://www.reddit.com/r/AskHistorians/comments/aetyc7/how_did_allied_forces_discover_the_names_of/
Intelligence has always been important in war. So by the time the Allies start fighting back the Germans you can imagine the amount of material they find, POWs they take, all to collect an incredible amount of information. Then by the time June 6 comes around, a minimum of 3 years have past where this process of collecting and identifying took place.