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="0" pages="0" files="0" subcats="0" xml:space="preserve">1947 births</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Board game designers</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Living people</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Role-playing game designers</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Role-playing game writers</c>
    </allcategories>
  </query>
</api>