Bug 157985 [Workbench] Add 'Hide toolbar' action to context menu
M2 The 'Hide toolbar' action should be added to the context menu on toolbars. That's where I first looked for it.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/WorkbenchActionBuilder.java
private IWorkbenchAction nextEditorAction;
    private IWorkbenchAction prevEditorAction;
    private IWorkbenchAction nextPerspectiveAction;
    private IWorkbenchAction prevPerspectiveAction;
    private IWorkbenchAction activateEditorAction;
    private IWorkbenchAction maximizePartAction;
    
    private IWorkbenchAction minimizePartAction;
    private IWorkbenchAction switchToEditorAction;
    private IWorkbenchAction openEditorDropDownAction;
    private IWorkbenchAction backwardHistoryAction;
    private IWorkbenchAction forwardHistoryAction;
    
    private IWorkbenchAction undoAction;
    private IWorkbenchAction redoAction;
    private IWorkbenchAction cutAction;
    private IWorkbenchAction copyAction;
    private IWorkbenchAction pasteAction;
    private IWorkbenchAction deleteAction;
    private IWorkbenchAction selectAllAction;
    private IWorkbenchAction findAction;
    private IWorkbenchAction printAction;
    private IWorkbenchAction revertAction;
    private IWorkbenchAction refreshAction;
    private IWorkbenchAction propertiesAction;
    private IWorkbenchAction quitAction;
    private IWorkbenchAction moveAction;
    private IWorkbenchAction renameAction;
    private IWorkbenchAction goIntoAction;
    private IWorkbenchAction backAction;