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 forwardAction;
    private IWorkbenchAction upAction;
    private IWorkbenchAction nextAction;
    private IWorkbenchAction previousAction;
    
    private IWorkbenchAction openWorkspaceAction;
    private IWorkbenchAction projectPropertyDialogAction;
    private IWorkbenchAction newWizardAction;
    private IWorkbenchAction newWizardDropDownAction;
    private IWorkbenchAction importResourcesAction;
    
    private IWorkbenchAction exportResourcesAction;
    IWorkbenchAction buildAllAction; 
    private IWorkbenchAction cleanAction;
    private IWorkbenchAction toggleAutoBuildAction;
    MenuManager buildWorkingSetMenu;
    private IWorkbenchAction quickStartAction;
    private IWorkbenchAction tipsAndTricksAction;
    private QuickMenuAction showInQuickMenu;
    private QuickMenuAction newQuickMenu;
    private IWorkbenchAction introAction;
    
    private IWorkbenchAction addBookmarkAction;
    private IWorkbenchAction addTaskAction;
    IWorkbenchAction buildProjectAction;
    private IWorkbenchAction openProjectAction;
    private IWorkbenchAction closeProjectAction;
    
    private IWorkbenchAction toggleCoolbarAction;