mobile-config-firefox/chrome/show_window_title_in_menubar.css

/* Shows window title in menubar */
/* Enable menubar for correct behavior */
@-moz-document url(chrome://browser/content/browser.xhtml){
  head{ display: block; position: fixed; width: 100vw; text-align: center }
  head > *{ display: none }
  head > title{ display: -moz-box; padding-top: 1px }
}