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>
    <pageswithprop gpwpcontinue="376" />
  </query-continue>
  <query>
    <pages>
      <page pageid="1" ns="0" title="メインページ" contentmodel="wikitext" pagelanguage="ja" touched="2020-06-24T06:30:19Z" lastrevid="2854" counter="226649" length="3298" />
      <page pageid="363" ns="0" title="Black Onyx" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:13:25Z" lastrevid="2685" counter="4199" length="1197" />
      <page pageid="366" ns="0" title="Pandora&#039;s box" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:14:07Z" lastrevid="2687" counter="4000" length="1010" />
      <page pageid="367" ns="0" title="Angel&#039;s Fear" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:14:37Z" lastrevid="2688" counter="4412" length="930" />
      <page pageid="368" ns="0" title="For Future feat. Final Fantasy ~Prelude~" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:15:07Z" lastrevid="2689" counter="3862" length="1699" />
      <page pageid="370" ns="0" title="Stars" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:15:38Z" lastrevid="2690" counter="4560" length="821" />
      <page pageid="371" ns="0" title="となりの手" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:16:03Z" lastrevid="2691" counter="4485" length="1260" />
      <page pageid="373" ns="0" title="Broken Sky" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:16:23Z" lastrevid="2692" counter="4190" length="849" />
      <page pageid="374" ns="0" title="かえるのテーマ" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:16:50Z" lastrevid="2693" counter="4243" length="1461" />
      <page pageid="375" ns="0" title="Heal the" contentmodel="wikitext" pagelanguage="ja" touched="2019-03-03T17:17:10Z" lastrevid="2694" counter="4323" length="493" />
    </pages>
  </query>
</api>