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>
    <allfileusages gafcontinue="Contact-mgr.png|26" />
  </query-continue>
  <query>
    <pages>
      <page pageid="20" ns="0" title="Managing Content" />
      <page pageid="24" ns="0" title="User States/Roles" />
      <page pageid="38" ns="0" title="Child Page Sorting" />
      <page pageid="41" ns="0" title="Collaboration Tools" />
      <page pageid="88" ns="0" title="ACNM Clear Cache Tool" />
      <page pageid="97" ns="0" title="AATB Group Search" />
      <page pageid="125" ns="0" title="American College of Nurse-Midwives (ACNM)" />
      <page pageid="126" ns="0" title="American Association of Tissue Banks (AATB)" />
    </pages>
  </query>
</api>