resources/lib/ooui/themes/wikimediaui/images/icons/window-invert.svg
<?xml version="1.0" encoding="UTF-8"?><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 20 20"><title>
window
</title><g fill="#fff"><path d="M2 2a2 2 0 0 0-2 2v12a2 2 0 0 0 2 2h16a2 2 0 0 0 2-2V4a2 2 0 0 0-2-2zm0 2h16v12H2z"/><path d="M4 6h12v2H4z"/></g></svg>