You are looking at the HTML representation of the mFormat?> 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>
    <general mainpage="Main Page" base="http://www.barcampbank.org/index.php/Main_Page" sitename="BarCampBank's Wiki" generator="MediaWiki 1.10.1" case="first-letter" rights="" />
  </query>
</api>