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 atcontinue="LC_CARDLIST_TBODY_SET2_Black" />
  </query-continue>
  <query>
    <alltransclusions>
      <t ns="10" title="テンプレート:LC CARD" />
      <t ns="10" title="テンプレート:LC CARD2" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY PR" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 ALL" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 Black" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 Blue" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 Orange" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 Purple" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET1 White" />
      <t ns="10" title="テンプレート:LC CARDLIST TBODY SET2 ALL" />
    </alltransclusions>
  </query>
</api>