If you use Emacs and you are curious how something works, look up the function/command/keybinding with the built-in help. It will usually contain a link to the

If you use Emacs and you are curious how something works, look up the function/command/keybinding with the built-in help. It will usually contain a link to the Emacs source code implementing it. At least I have learned a lot from reading how these things fit together in the code, and occasionally replacing a definition entirely or creating advice around it. It's a very easy environment to do so in, because the documentation is automatically linked to the relevant source code, so you never have to get stuck at something because you don't know what it does under the hood.