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-continue>
    <allfileusages gafcontinue="Bls.gif|1731" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1331" ns="0" title="Blank Character Sheet" />
      <page pageid="1721" ns="0" title="Numbers" />
      <page pageid="1777" ns="0" title="Romance Sheet" />
      <page pageid="1895" ns="0" title="Foundation Stone" />
      <page pageid="1899" ns="0" title="Foundation Stone Monk" />
      <page pageid="1900" ns="10" title="Template:Foundation Stone Monk" />
      <page pageid="2062" ns="0" title="Magic Wheel" />
      <page pageid="2063" ns="10" title="Template:Magic Wheel Beggar" />
      <page pageid="2066" ns="0" title="Magic Wheel Beggar" />
    </pages>
  </query>
</api>