chromium/ui/file_manager/file_manager/foreground/images/files/ui/external_link.svg

<svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 20 20">
  <path d="M15 15H5V5h4V3H5C4 3 3 4 3 5v10c0 1 1 2 2 2h10c1 0 2-1 2-2v-4h-2v4zM11 3v2h2.5L7 11.5 8.5 13 15 6.5V9h2V3h-6z"/>
</svg>