gecko-dev/layout/tools/reftest/reftest.xul

<!-- vim: set shiftwidth=4 tabstop=8 autoindent expandtab: -->
<!-- This Source Code Form is subject to the terms of the Mozilla Public
   - License, v. 2.0. If a copy of the MPL was not distributed with this
   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
<?xml-stylesheet type="text/css" href="data:text/css,

%23_box_windowsDefaultTheme:-moz-system-metric(windows-default-theme) {
  display: none;
}

" ?>

<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
        id="reftest-window"
        hidechrome="true"
        onload="OnRefTestLoad();"
        onunload="OnRefTestUnload();"
        style="background:white; overflow:hidden"
        >
    <script type="application/ecmascript" src="reftest.js" />
    <!-- The reftest browser element is dynamically created, here -->
</window>