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="4" pages="4" files="0" subcats="0" xml:space="preserve">Brake system maintenance</c>
      <c size="4" pages="4" files="0" subcats="0" xml:space="preserve">Chassis maintenance</c>
      <c size="9" pages="9" files="0" subcats="0" xml:space="preserve">Club</c>
      <c size="2" pages="2" files="0" subcats="0" xml:space="preserve">Club events</c>
      <c size="4" pages="4" files="0" subcats="0" xml:space="preserve">Cosmetic modification</c>
      <c size="2" pages="2" files="0" subcats="0" xml:space="preserve">Drivetrain maintenance</c>
      <c size="2" pages="1" files="0" subcats="1" xml:space="preserve">Electrical maintenance</c>
      <c size="5" pages="4" files="0" subcats="1" xml:space="preserve">Engine maintenance</c>
      <c size="1" pages="1" files="0" subcats="0" xml:space="preserve">Error codes</c>
      <c size="1" pages="1" files="0" subcats="0" xml:space="preserve">Fuel system maintenance</c>
    </allcategories>
  </query>
  <query-continue>
    <allcategories acfrom="Guides" />
  </query-continue>
</api>