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>
    <querypage name="Ancientpages">
      <results>
        <page value="20130509165825" timestamp="2013-05-09T16:58:25Z" ns="0" title="MediaWikiHelper" />
        <page value="20130509180421" timestamp="2013-05-09T18:04:21Z" ns="0" title="AboutAVA" />
        <page value="20130510113731" timestamp="2013-05-10T11:37:31Z" ns="0" title="AVA Starter Version" />
        <page value="20130513141941" timestamp="2013-05-13T14:19:41Z" ns="0" title="About AVA" />
        <page value="20130515152414" timestamp="2013-05-15T15:24:14Z" ns="0" title="AVA Database Management Reference" />
        <page value="20130515214346" timestamp="2013-05-15T21:43:46Z" ns="0" title="AVA SQL" />
        <page value="20130521113442" timestamp="2013-05-21T11:34:42Z" ns="0" title="Main Page" />
        <page value="20140513173208" timestamp="2014-05-13T17:32:08Z" ns="0" title="Data Types" />
        <page value="20210716020456" timestamp="2021-07-16T02:04:56Z" ns="0" title="Quick Start Guide" />
      </results>
    </querypage>
  </query>
</api>