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="003_cowboy.png" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2118" ns="6" title="File:000 smiley normal.png" />
      <page pageid="4228" ns="6" title="File:001 default.png" />
      <page pageid="4077" ns="6" title="File:001 gravity.png" />
      <page pageid="4066" ns="6" title="File:001 little girl.png" />
      <page pageid="2119" ns="6" title="File:001 smiley grin.png" />
      <page pageid="3539" ns="6" title="File:002 grin.png" />
      <page pageid="4078" ns="6" title="File:002 keys.png" />
      <page pageid="4067" ns="6" title="File:002 little boy.png" />
      <page pageid="4229" ns="6" title="File:002 pinwheel.png" />
      <page pageid="2120" ns="6" title="File:002 smiley tongue.png" />
    </pages>
  </query>
</api>