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>
    <alllinks alcontinue="Bimbisara" />
  </query-continue>
  <query>
    <alllinks>
      <l ns="0" title="Babylon" />
      <l ns="0" title="Babylonia" />
      <l ns="0" title="Babylonian Empire" />
      <l ns="0" title="Battle of Adrianople" />
      <l ns="0" title="Battle of Gaugamela" />
      <l ns="0" title="Battle of Marathon" />
      <l ns="0" title="Battle of Salamis" />
      <l ns="0" title="Battle of Zama" />
      <l ns="0" title="Battle of the Hydaspes River" />
      <l ns="0" title="Battle of the Teutoburg Forest" />
    </alllinks>
  </query>
</api>