I would say: History. And I don't mean giving one or two examples during a full computer science course. I mean a full course on History. Important figures from the past who had an impact on technology. Like Augusta Ada King, who was in a way, already thinking of how to write computer programs. I would say the most valuable things what we can learn from history are "What they did" and especially "Why they did what they did". Imagine you would like to master a programming language. I would say one of the key factors is not knowing how to program, but knowing how it actually works. Underwater. Why the language was done in this way (e.g. performance, structural) and not many of the other ways?. Who where the people behind the language? What was their life like? What choices did they make and why? What could they have done better? There are plenty of sources online to find this out yourself, but it demands a lot of time. Having a course on this regarding the most fundamental topics has a lot of value for a developer. As a developer you want to reach the point of saying: Ask my anything about my field of expertise. I know it all.