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>
    <alltransclusions gatcontinue="Extension_DPL|46" />
  </query-continue>
  <query>
    <pages>
      <page pageid="28" ns="0" title="Fate Testarossa" />
      <page pageid="29" ns="0" title="Tokiko Amagawa" />
      <page pageid="30" ns="0" title="Madoka Kaname" />
      <page pageid="32" ns="0" title="Minako Aino" />
      <page pageid="35" ns="0" title="Ren Aizawa" />
      <page pageid="42" ns="0" title="Nanoha Takamachi" />
      <page pageid="1543" ns="10" title="Template:Documentation subpage" />
      <page pageid="1544" ns="10" title="Template:TOC limit/doc" />
      <page pageid="1545" ns="10" title="Template:Tl" />
      <page pageid="1546" ns="10" title="Template:Tlx" />
    </pages>
  </query>
</api>