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="20110223163019" timestamp="2011-02-23T16:30:19Z" ns="0" title="Pošta Bílina Zámecká" />
        <page value="20110303173017" timestamp="2011-03-03T17:30:17Z" ns="0" title="Pošta Bílina-Mostecké Předměstí" />
        <page value="20110303174535" timestamp="2011-03-03T17:45:35Z" ns="0" title="Pošta Bílina-Teplické Předměstí" />
        <page value="20110303174858" timestamp="2011-03-03T17:48:58Z" ns="0" title="Pošta Bystřany" />
        <page value="20110303175138" timestamp="2011-03-03T17:51:38Z" ns="0" title="Pošta Dubí Ruská" />
        <page value="20110304071411" timestamp="2011-03-04T07:14:11Z" ns="0" title="Pošta Dubí-Běhánky" />
        <page value="20110304071757" timestamp="2011-03-04T07:17:57Z" ns="0" title="Pošta Dubí-Pozorka" />
        <page value="20110304072155" timestamp="2011-03-04T07:21:55Z" ns="0" title="Pošta Duchcov" />
        <page value="20110304073035" timestamp="2011-03-04T07:30:35Z" ns="0" title="Pošta Háj u Duchcova" />
        <page value="20110304073344" timestamp="2011-03-04T07:33:44Z" ns="0" title="Pošta Hostomice" />
      </results>
    </querypage>
  </query>
  <query-continue>
    <querypage qpoffset="10" />
  </query-continue>
</api>