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>
    <allpages apcontinue="Enterprise_Node_Architecture" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="74" ns="0" title="Billing" />
      <p pageid="7" ns="0" title="Branching strategy" />
      <p pageid="16" ns="0" title="Build, Deploy and Test For Development" />
      <p pageid="13" ns="0" title="Business Architecture" />
      <p pageid="17" ns="0" title="Business Architecture For AccountIT" />
      <p pageid="38" ns="0" title="Business Architecture For Enterprise" />
      <p pageid="54" ns="0" title="Business Architecture For Internal" />
      <p pageid="51" ns="0" title="Business Architecture For Platform" />
      <p pageid="42" ns="0" title="Categories" />
      <p pageid="99" ns="0" title="Conceptual Data Model For AccountIT" />
    </allpages>
  </query>
</api>