You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <allcategories>
      <c size="3" pages="2" files="0" subcats="1" xml:space="preserve">.NET</c>
      <c size="1" pages="1" files="0" subcats="0" xml:space="preserve">.NET FAQ</c>
      <c size="5" pages="5" files="0" subcats="0" xml:space="preserve">5250 Emulators</c>
      <c size="7" pages="6" files="0" subcats="1" xml:space="preserve">API</c>
      <c size="25" pages="22" files="0" subcats="3" xml:space="preserve">Administration</c>
      <c size="1" pages="1" files="0" subcats="0" xml:space="preserve">Article boilerplate templates</c>
      <c size="33" pages="33" files="0" subcats="0" xml:space="preserve">Article redirects to categories</c>
      <c size="5" pages="4" files="0" subcats="1" xml:space="preserve">Articles to verify</c>
      <c size="2" pages="2" files="0" subcats="0" xml:space="preserve">Articles with unknown information</c>
      <c size="10" pages="10" files="0" subcats="0" xml:space="preserve">BPCS</c>
    </allcategories>
  </query>
  <query-continue>
    <allcategories acfrom="Backup and Recovery" />
  </query-continue>
</api>