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="Human-female-front-and-back.jpg|126" />
  </query-continue>
  <query>
    <pages>
      <page pageid="415" ns="0" title="BDSM Symbols" />
      <page pageid="601" ns="0" title="Findamunch.com" />
      <page pageid="654" ns="0" title="Erotic Awakening" />
      <page pageid="685" ns="0" title="Carter/Johnson Leather Library" />
      <page pageid="687" ns="0" title="Leather Archives and Museum" />
      <page pageid="710" ns="0" title="Rainbow Culture" />
      <page pageid="841" ns="0" title="Goat Week" />
      <page pageid="861" ns="0" title="Slave positions" />
    </pages>
  </query>
</api>