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>
    <allimages gaicontinue="300px-Flake-keyboard-eyes.jpg" />
  </query-continue>
  <query>
    <pages>
      <page pageid="727" ns="6" title="File:1182870547 mid.jpg" />
      <page pageid="677" ns="6" title="File:1512 browning wideweb 430x279.jpg" />
      <page pageid="699" ns="6" title="File:162317 beowulf and grendel l.jpg" />
      <page pageid="114" ns="6" title="File:20791457.jpg" />
      <page pageid="115" ns="6" title="File:20791457.jpg.jpg" />
      <page pageid="469" ns="6" title="File:248px-Morgan wiki.jpg" />
      <page pageid="2504" ns="6" title="File:250px-Sindy.jpg" />
      <page pageid="661" ns="6" title="File:260px-JabbaTheHutt.jpg" />
      <page pageid="861" ns="6" title="File:28686409aaaaa.jpg" />
      <page pageid="2992" ns="6" title="File:29CS.jpg" />
    </pages>
  </query>
</api>