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>
    <allredirects arcontinue="Batty" />
  </query-continue>
  <query>
    <allredirects>
      <r ns="0" title="Back To The Future" />
      <r ns="0" title="Back To The Future Part II" />
      <r ns="0" title="Back To The Future Part III" />
      <r ns="0" title="Back to Skool" />
      <r ns="0" title="Bacteria" />
      <r ns="0" title="Bajtek" />
      <r ns="0" title="Barbarian" />
      <r ns="0" title="Batman the Caped Crusader" />
      <r ns="0" title="Battle City (1993)" />
      <r ns="0" title="Battlezone" />
    </allredirects>
  </query>
</api>