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>
    <pages>
      <page pageid="1" ns="0" title="Main Page" />
    </pages>
    <backlinks>
      <bl pageid="937" ns="2" title="User:Gregory.Szorc" />
      <bl pageid="1301" ns="0" title="Main page" />
      <bl pageid="2106" ns="0" title="Central Authentication Service" />
      <bl pageid="2519" ns="0" title="Network Access and Leaving the University Policy" />
      <bl pageid="3046" ns="0" title="PHP" />
      <bl pageid="3106" ns="0" title="The World's Most Powerful Learning Environment" />
      <bl pageid="3272" ns="12" title="Help:Cheat sheet" />
      <bl pageid="3285" ns="2" title="User:Melissa.Delucchi" />
      <bl pageid="3922" ns="1" title="Talk:Wiki farm proposal" />
      <bl pageid="5160" ns="0" title="Case Wiki" />
    </backlinks>
  </query>
</api>