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="215" ns="6" title="File:Amp4 u5.jpg" />
      <page pageid="231" ns="6" title="File:De-icer-jugs.jpg" />
      <page pageid="3" ns="6" title="File:Fixjunk.jpg" />
      <page pageid="213" ns="6" title="File:Hihi polar raw.gif" />
      <page pageid="244" ns="6" title="File:Meat chili closeup.jpg" />
      <page pageid="245" ns="6" title="File:Meat chili steam.jpg" />
      <page pageid="220" ns="6" title="File:Trunk sub 1.jpg" />
      <page pageid="221" ns="6" title="File:Trunk sub 2.jpg" />
    </pages>
  </query>
</api>