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>
    <pages>
      <page pageid="1" ns="0" title="Main Page">
        <links>
          <pl ns="0" title="100 Greatest Supercars of All Time" />
          <pl ns="0" title="Getting Started With Wiki" />
          <pl ns="0" title="Koenigsegg Agera" />
          <pl ns="0" title="Mercedes-Benz SLS AMG" />
          <pl ns="0" title="Porsche 918" />
          <pl ns="0" title="SandBox" />
          <pl ns="0" title="The 10 Worst Supercars of All Time" />
          <pl ns="0" title="The 50 Best Supercars of All Time" />
        </links>
      </page>
    </pages>
  </query>
</api>