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="DisplayAsOL|255" />
  </query-continue>
  <query>
    <pages>
      <page pageid="242" ns="14" title="Category:Fluttershy episode" />
      <page pageid="246" ns="14" title="Category:Applejack episode" />
      <page pageid="247" ns="14" title="Category:Rainbow Dash episode" />
      <page pageid="248" ns="14" title="Category:Rarity episode" />
      <page pageid="249" ns="14" title="Category:Pinkie Pie episode" />
      <page pageid="250" ns="14" title="Category:Twilight Sparkle episode" />
      <page pageid="251" ns="14" title="Category:Spike episode" />
      <page pageid="252" ns="14" title="Category:Apple Bloom episode" />
      <page pageid="253" ns="14" title="Category:Sweetie Belle episode" />
      <page pageid="254" ns="14" title="Category:Scootaloo episode" />
    </pages>
  </query>
</api>