My application has many actions which can be used without using a hotkey, such as closing a tab. These actions are available in the menu bar where the hotkey for that action (Ctrl+W) is also listed.
However there are also actions that are only available through a hotkey, such as Ctrl+Tab which, while holding Ctrl, opens a sort of tab manager. This tab manager cannot be used without holding Ctrl, and as such is not available as a separate action. Since there is no entry for this in the menu bar, I don't know where to list this hotkey.
How do I inform my users of this hidden hotkey?