It’s surprising to me that many people still don’t know where some of the keystrokes we use everyday in our editors came from. The most famous example, I suppose, is why Vi(m) uses the j k h l keys for cursor navigation but there are others.
The thing with Emacs and Vi is that they’re really old for software and when they were developed, keyboards didn’t look at all like they do now. Anuj Kumar has a short post that explains all this, primarily for Emacs and Vi but also for more general frameworks like X11 and the CUA.
If you’re already familiar with this lore, you probably won’t learn much new except for the names of some of the people who influenced the design in various ways. If you aren’t familiar with it, take a look at Kumar’s post. If you’re using Emacs or Vi(m), you really should know this stuff.