How to find the function and the menu (or button) corresponding to a shortcut (knowing only shortcut keys)? I wonder how to find the function and the menu (or button) corresponding to a shortcut (if I have only the shortcut and no idea of what it does) ?

For instance : if in a video I see one maker doing "[Shift] + [S]" and I would like to find the explanations corresponding to this shortcut, at least in the manual... How can I find this ?
(Default Keymap does not help to this in the manual)

Thank you for your attention and your kindness, and maybe for a good answer ! :)
By searching for it
You can look through Blender's UI and check all the menus. It is often possible to find a lot using this obvious and simple way, or you could also search the key map in the user preferences(F4 -&gt; p):

Note that you can have one hotkey that does different things depending on the context(what editor or thing you hover your mouse above, what mode you are in, what you have selected and things like that).