You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <pages>
      <page pageid="47" ns="0" title="Bifrost (アレンジ)" />
      <page pageid="7" ns="0" title="Information" />
      <page pageid="150" ns="0" title="Life of Eorzea" />
      <page pageid="137" ns="0" title="SIGMA Because" />
      <page pageid="40" ns="0" title="Shilverlight Wings -時を渡る翼-" />
      <page pageid="5" ns="0" title="Work" />
      <page pageid="20" ns="0" title="コミックマーケットC78" />
      <page pageid="22" ns="0" title="コミックマーケットC79" />
      <page pageid="38" ns="0" title="楽曲使用ガイダンス" />
      <page pageid="75" ns="0" title="潮鳴り -in the lights-" />
    </pages>
  </query>
</api>