You are looking at the HTML representation of the XML format.
HTML is good for debugging, but probably is not suitable for your application.
Please see "format" parameter documentation at the API help for more information. 
<?xml version="1.0" encoding="utf-8"?>
<api>
  <query>
    <pages>
      <page ns="0" title="API" missing="" />
      <page pageid="1" ns="0" title="Main Page">
        <revisions>
          <rev revid="1" pageid="1" oldid="1" user="MediaWiki default" anon="" timestamp="2008-09-10T19:31:52Z"><big>'''MediaWiki has been successfully installed.'''</big>

Consult the [http://meta.wikimedia.org/wiki/Help:Contents User's Guide] for information on using the wiki software.

== Getting started ==

* [http://www.mediawiki.org/wiki/Help:Configuration_settings Configuration settings list]
* [http://www.mediawiki.org/wiki/Help:FAQ MediaWiki FAQ]
* [http://mail.wikimedia.org/mailman/listinfo/mediawiki-announce MediaWiki release mailing list]</rev>
        </revisions>
      </page>
    </pages>
  </query>
</api>