You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
See complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query>
    <pages>
      <page pageid="1" ns="0" title="Main Page">
        <revisions>
          <rev user="Hannibal" timestamp="2012-09-12T21:11:36Z" comment="Undo revision 309660 by [[Special:Contributions/Shemhazi|Shemhazi]] ([[User talk:Shemhazi|talk]])" />
          <rev user="Shemhazi" timestamp="2012-08-17T01:20:44Z" comment="Replaced content with &quot;I am a troll hehehehe ;) gl cunts fucking low life court rivals players go and play reall bb u sick sluts fuck!&quot;" />
          <rev user="Hannibal" timestamp="2012-05-04T00:52:29Z" comment="" />
          <rev user="24.123.146.46" anon="" timestamp="2012-05-03T18:35:35Z" comment="" />
          <rev user="178.239.58.143" anon="" timestamp="2012-05-03T17:40:34Z" comment="" />
        </revisions>
      </page>
    </pages>
  </query>
  <query-continue>
    <revisions rvstartid="309440" />
  </query-continue>
</api>