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="Im_synth_p14_rust.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="28" ns="6" title="File:Im synth p10 pm.png" />
      <page pageid="31" ns="6" title="File:Im synth p14 phong.png" />
      <page pageid="35" ns="6" title="File:Im synth p14 metal.png" />
      <page pageid="6" ns="6" title="File:Fry username password.jpg" />
      <page pageid="29" ns="6" title="File:Im synth p11 scatter.png" />
      <page pageid="39" ns="6" title="File:Im synth p14 mask.png" />
      <page pageid="32" ns="6" title="File:Im synth p14 ramp.png" />
      <page pageid="36" ns="6" title="File:Im synth p14 hg.png" />
      <page pageid="30" ns="6" title="File:Im synth p12 hg.png" />
      <page pageid="38" ns="6" title="File:Im synth p14 combo.png" />
    </pages>
  </query>
</api>