Adding Shortcuts and editorToolbar buttons

So, I have a few questions all generally related to adding editorToolbar buttons, I’ll just make a list below of them

  1. How do you add a new shortcut to the ControlPanel? I can see that other editorToolbar buttons have ((shortcut-name)) in the shortcuts field that pulls the keyboard combination from what I can only assume is the keyboard shortcuts section in the Control Panel, and would like to do that, rather how I have been doing it in the past, with the shortcuts field having the shortcut put in it (ie having “alt + s” instead of “((stamp))”)

  2. What sort of transclusion is double round brackets, exactly? I’m not sure how to use them, and very, very rarely see them.

Any help is appreciated!

See https://tiddlywiki.com/#How%20to%20create%20keyboard%20shortcuts

That syntax is not for transclusions but rather for Keyboard Shortcut Descriptors: https://tiddlywiki.com/#Keyboard%20Shortcut%20Descriptor