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>
    <pages>
      <page ns="0" title="API" missing="" />
      <page pageid="1" ns="0" title="Main Page">
        <revisions>
          <rev user="Andy" timestamp="2015-08-31T23:27:36Z" comment="/* Something interesting may be here one day... */" contentformat="text/x-wiki" contentmodel="wikitext" xml:space="preserve">[[GeorgeWBush]] (AKA [[User:Sarah|Sarah]]) would like to point out that he/she/it believes '''this is a wiki''', in case you were in any doubt about that.  It is debatable however as you do need to sign up with a valid email address to contribute to it.

==Something interesting may be here one day...==

...but until then, maybe you were looking for:

* [http://strugglers.net/~andy/blog/ Andy's Blog]</rev>
        </revisions>
      </page>
    </pages>
  </query>
</api>