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"?>
    <backlinks blcontinue="0|Main_Page|6100" />
      <bl pageid="1697" ns="0" title="Home" redirect="" />
      <bl pageid="1992" ns="0" title="Frequently Asked Questions" />
      <bl pageid="2307" ns="2" title="User:Lozzo/Sandbox" />
      <bl pageid="2320" ns="3" title="User talk:Lozzo" />
      <bl pageid="2429" ns="5" title="LinuxMCE talk:Community Portal" />
      <bl pageid="5349" ns="0" title="Main Page pre 2011" redirect="" />
      <bl pageid="6095" ns="12" title="Help:Editing advanced" />
      <bl pageid="6096" ns="10" title="Template:Nav" />
      <bl pageid="6097" ns="0" title="Contributing to LMCE" />
      <bl pageid="6098" ns="0" title="1. Where do I start?" />