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">*</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">+X/+Yカウンター</c>
      <c size="14" pages="14" files="0" subcats="0" xml:space="preserve">+X/+Yカウンター</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Archenemyの未評価カード</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Archenemyの未評価カード</c>
      <c size="41" pages="41" files="0" subcats="0" xml:space="preserve">Explorers of Ixalanの未評価カード</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Global Series: Jiang Yanggu &amp; Mu Yanlingの未評価カード</c>
      <c size="12" pages="12" files="0" subcats="0" xml:space="preserve">Heroes of the Realmの未評価カード</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Jumpstart: Historic Horizonsの未評価カード</c>
      <c size="0" pages="0" files="0" subcats="0" xml:space="preserve">Jumpstartの未評価カード</c>
    </allcategories>
  </query>
  <query-continue>
    <allcategories acfrom="Magic: The Gathering Arena" />
  </query-continue>
</api>