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>
    <backlinks>
      <bl pageid="1547" ns="12" title="Help:Links" />
      <bl pageid="1757" ns="0" title="Wiki Format Sheet" />
      <bl pageid="2133" ns="0" title="Short Philosophy Video for Discussions" />
      <bl pageid="2498" ns="0" title="Learning Community -- Summer Benin 2013" />
      <bl pageid="2499" ns="0" title="Philosophy of Culture - Benin Summer 2013" />
      <bl pageid="2577" ns="0" title="Benin Learning Community 2014" />
      <bl pageid="2581" ns="0" title="Philosophy of Culture: Benin" />
    </backlinks>
  </query>
</api>