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-continue>
    <backlinks blcontinue="0|Main_Page|595" />
  </query-continue>
  <query>
    <backlinks>
      <bl pageid="26" ns="0" title="FairShares Model" />
      <bl pageid="28" ns="0" title="Background" />
      <bl pageid="29" ns="0" title="Social Licence" />
      <bl pageid="30" ns="0" title="Social Enterprise Europe" />
      <bl pageid="110" ns="0" title="FairShares Articles of Association" />
      <bl pageid="121" ns="0" title="Model constitutions" />
      <bl pageid="495" ns="0" title="Co-operative and Social Enterprise Support Ltd" />
      <bl pageid="521" ns="0" title="What&#039;s New in V2.0?" />
      <bl pageid="593" ns="0" title="Initial Social Audit" />
      <bl pageid="594" ns="0" title="Initial Participation Audit" />
    </backlinks>
  </query>
</api>