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="20100514114211" timestamp="2010-05-14T11:42:11Z" ns="0" title="Infoboxtest" />
        <page value="20100827072821" timestamp="2010-08-27T07:28:21Z" ns="0" title="Marie-Antoinette" />
        <page value="20101009154402" timestamp="2010-10-09T15:44:02Z" ns="0" title="Catégorie:Siefar dictionary" />
        <page value="20101028170452" timestamp="2010-10-28T17:04:52Z" ns="0" title="Main Page" />
        <page value="20101113163005" timestamp="2010-11-13T16:30:05Z" ns="0" title="Claire-Josèphe-Hyppolite Léris" />
        <page value="20101203123658" timestamp="2010-12-03T12:36:58Z" ns="0" title="Agnes of France (a1265-1325)" />
        <page value="20101209092758" timestamp="2010-12-09T09:27:58Z" ns="0" title="Suzanne Alexe" />
        <page value="20101209124244" timestamp="2010-12-09T12:42:44Z" ns="0" title="Marie-Madeleine Pioche de La Vergne" />
        <page value="20101209131428" timestamp="2010-12-09T13:14:28Z" ns="0" title="Madeleine du Bois de Fontaines-Marans" />
        <page value="20101209150216" timestamp="2010-12-09T15:02:16Z" ns="0" title="Marie du Tixier" />
      </results>
    </querypage>
  </query>
</api>