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>
    <querypage qpoffset="10" />
  </query-continue>
  <query>
    <querypage name="Ancientpages">
      <results>
        <page value="20080121221107" timestamp="2008-01-21T22:11:07Z" ns="0" title="Booting from Gentoo Live CD" />
        <page value="20080122014044" timestamp="2008-01-22T01:40:44Z" ns="0" title="Alsa" />
        <page value="20080331214001" timestamp="2008-03-31T21:40:01Z" ns="0" title="Engr 310" />
        <page value="20080707193653" timestamp="2008-07-07T19:36:53Z" ns="0" title="Gmail IMAP" />
        <page value="20080912174559" timestamp="2008-09-12T17:45:59Z" ns="0" title="Vim" />
        <page value="20081104194201" timestamp="2008-11-04T19:42:01Z" ns="0" title="EE 492" />
        <page value="20081127061853" timestamp="2008-11-27T06:18:53Z" ns="0" title="Installing Gentoo" />
        <page value="20090218001254" timestamp="2009-02-18T00:12:54Z" ns="0" title="Java Bug" />
        <page value="20090917150308" timestamp="2009-09-17T15:03:08Z" ns="0" title="Kalman Filter" />
        <page value="20110824144244" timestamp="2011-08-24T14:42:44Z" ns="0" title="Old stuff" />
      </results>
    </querypage>
  </query>
</api>