gecko-dev/browser/base/content/browser.css

#search-bar {
  -moz-binding: url("chrome://browser/content/search.xml#searchbar");
}

/* ::::: print preview toolbar ::::: */

toolbar[printpreview="true"] {
  -moz-binding: url("chrome://global/content/printPreviewBindings.xml#printpreviewtoolbar");
}

#search-proxy-button {
  -moz-binding: url("chrome://browser/content/search.xml#searchBarDropMarker");
  -moz-user-focus: none;
}

#statusbar-updates {
  -moz-binding: url("chrome://mozapps/content/update/updates.xml#updateStatusbarNotification");
}