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="20150317174725" timestamp="2015-03-17T17:47:25Z" ns="0" title="Pagina principale" />
        <page value="20150318104443" timestamp="2015-03-18T10:44:43Z" ns="0" title="Galleria" />
        <page value="20150414141045" timestamp="2015-04-14T14:10:45Z" ns="0" title="La Ricerca dell arte" />
        <page value="20150414144234" timestamp="2015-04-14T14:42:34Z" ns="0" title="La ricerca dell’arte e le sue scoperte" />
        <page value="20150414144735" timestamp="2015-04-14T14:47:35Z" ns="0" title="Autore" />
        <page value="20150414150714" timestamp="2015-04-14T15:07:14Z" ns="0" title="Percezioni" />
        <page value="20160112150000" timestamp="2016-01-12T15:00:00Z" ns="0" title="Pagina di prova" />
        <page value="20170420092007" timestamp="2017-04-20T09:20:07Z" ns="0" title="Filosofia Estetica Applicata" />
      </results>
    </querypage>
  </query>
</api>