German here.
It's most of what we do in history class. We don't learn about a lot of decisive battles or war heroes though, we mostly learn about what lead up to the war. For example with WW1, we discussed a lot about to what degree germany was at fault for the war, and what could have been done differently to avoid it. With WW2 we mostly do Hitlers road to power, how he turned the republic into a dictatorship. We also discussed things like, why the constitution of the republic back then could allow something like that, and again, how could it have been avoided. There's also quite a lot about german resistance against the Nazi regime, why it was worth it to resist the Nazis, even though none of the attempts succesfully dethroned Hitler.