Mozilla/mozilla/extensions/cck/browser/resources/content/cckwizard/cckwizard-browser-overlay.xul

<?xml version="1.0"?>
<overlay id="cckwizardOverlay" xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
  <script src="chrome://browser/content/utilityOverlay.js"/>
  
  <menupopup id="menu_ToolsPopup">
    <menuitem label="CCK Wizard" insertafter="devToolsSeparator" accesskey="z" 
              oncommand="window.openDialog('chrome://cckwizard/content/cckwizard.xul','cckwizard','chrome,centerscreen');"
              onclick="checkForMiddleClick(this, event);"/>
  </menupopup>
</overlay>