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>
    <alllinks galcontinue="Behavioral_targeting|21" />
  </query-continue>
  <query>
    <pages>
      <page pageid="26" ns="0" title="Beyond the banner" />
      <page pageid="81" ns="0" title="Fold" />
      <page pageid="124" ns="0" title="Rich media" />
      <page pageid="195" ns="0" title="GIF" />
      <page pageid="249" ns="0" title="Skyscraper" />
      <page pageid="334" ns="0" title="After the fold" />
      <page pageid="450" ns="0" title="Above the fold" />
      <page pageid="451" ns="0" title="Below the fold" />
      <page pageid="458" ns="0" title="Behavioral targeting" />
      <page pageid="460" ns="0" title="Onsite behavioral targeting" />
    </pages>
  </query>
</api>