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>
    <pages>
      <page pageid="127" ns="0" title="Bad Case of Harpies" contentmodel="wikitext" pagelanguage="en" touched="2016-09-21T11:03:24Z" lastrevid="539" counter="5820" length="2833" />
      <page pageid="214" ns="0" title="Descent Into Avernus" contentmodel="wikitext" pagelanguage="en" touched="2023-04-25T13:13:36Z" lastrevid="914" counter="1975" length="644" />
      <page pageid="14" ns="0" title="Lost Mine of Phandelver" contentmodel="wikitext" pagelanguage="en" touched="2015-03-03T01:51:46Z" lastrevid="92" counter="1673" length="394" />
      <page pageid="23" ns="0" title="Primeval Thule" contentmodel="wikitext" pagelanguage="en" touched="2020-11-02T06:44:04Z" lastrevid="781" counter="29629" length="3313" />
      <page pageid="177" ns="0" title="Sword and Memery" contentmodel="wikitext" pagelanguage="en" touched="2021-09-18T00:38:13Z" lastrevid="881" counter="30582" length="2866" />
      <page pageid="13" ns="0" title="The Rift Wars" contentmodel="wikitext" pagelanguage="en" touched="2020-11-02T06:04:06Z" lastrevid="768" counter="35968" length="6655" />
      <page pageid="218" ns="0" title="Violet Awakeners" contentmodel="wikitext" pagelanguage="en" touched="2023-03-17T03:34:26Z" lastrevid="912" counter="3613" length="2069" />
    </pages>
  </query>
</api>