How to Find What a Particular Keyboard Shortcut Does? How can I find the command triggered by a keyboard shortcut without activating it in any given application?

When I press a keyboard shortcut, the top-level menu is highlighted, but, beyond that, I don't get much information about where the command is located, or what exactly it does. Sometimes I discover a key combination (by accident or guessing) that does more or less what I want but I can't find the details in documentation because I don't know the name of the command.
You can find the name of every shortcut in an app by using a free app called CheatSheet.