<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg">
  <g fill="orange">
    <rect width="100" height="100" fill="red"/>
    <rect width="100" height="100" fill="url(#notthere)"/>
    <g fill="black">
      <text x="10" y="130">The above rect should be BLACK.</text>
      <text x="10" y="150">SVG 1.1 FULL says there should be a "highly perceivable error" message when an invalid fill url is used.</text>
      <text x="10" y="170">Browsers don't display such an error, instead use some sort of fill-fallback.</text>
      <text x="10" y="190">Opera falls back to 'black' (default), Firefox to 'none', and Safari to 'black'.  Bug 11017.</text>
    </g>
  </g>
</svg>