Binding default namespaces to elements with #FIXED ATTLISTs

<!ATTLIST svg xmlns (CDATA) #FIXED "http://www.w3.org/2000/svg">

<svg width="12cm" height="10cm">
  <ellipse rx="110" ry="130" />
  <rect x="4cm" y="1cm" width="3cm" height="6cm" />
</svg>