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="M. Lucretius Agricola" timestamp="2006-05-12T02:03:41Z" comment="change macellum link to point to non-category page" />
          <rev user="M. Lucretius Agricola" timestamp="2006-05-15T08:18:41Z" comment="fix broken link" />
          <rev user="Marcus Octavius Gracchus" timestamp="2006-05-15T22:35:24Z" comment="revert - we need a real Annals article there..." />
          <rev user="Marcus Octavius Gracchus" timestamp="2006-06-20T14:34:41Z" comment="+citizen policy statement" />
          <rev user="Marcus Octavius Gracchus" timestamp="2006-06-20T14:41:03Z" comment="fix link" />
        </revisions>
      </page>
    </pages>
  </query>
  <query-continue>
    <revisions rvstartid="3943" />
  </query-continue>
</api>