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="97" ns="10" title="Template:Infobox Govt Agency" />
      <page pageid="742" ns="0" title="San Pedro Sula" />
      <page pageid="891" ns="0" title="Pages 166 - 175" />
      <page pageid="892" ns="0" title="Pages 166- 175" />
      <page pageid="1038" ns="0" title="Earth Science 7 - Russia" />
    </pages>
  </query>
</api>