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="7438" ns="0" title="Main Page">
        <revisions>
          <rev user="Vladimir" timestamp="2012-10-20T19:56:39Z" comment="Удалено содержимое страницы" />
          <rev user="Vladimir" timestamp="2012-10-20T19:55:44Z" comment="Защищена страница «[[Main Page]]» ([edit=autoconfirmed] (бессрочно) [move=autoconfirmed] (бессрочно))" />
          <rev user="118.96.202.129" anon="" timestamp="2012-10-20T19:52:33Z" />
          <rev user="118.96.202.129" anon="" timestamp="2012-10-20T19:52:14Z" comment="Новая страница: «Workstation tasks are just like entertaining.  Offer are you currently using the computer system system even though you might each twenty-four hours whether or over …»" />
        </revisions>
      </page>
    </pages>
  </query>
</api>