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="1385" ns="0" title="Appendix" contentmodel="wikitext" pagelanguage="en" touched="2023-06-13T20:52:40Z" lastrevid="2645" counter="37596" length="31934" />
      <page pageid="1434" ns="0" title="CEDAR/Cancer Specific Rules" contentmodel="wikitext" pagelanguage="en" touched="2024-08-14T15:11:08Z" lastrevid="2734" counter="21418" length="18640" />
      <page pageid="1383" ns="0" title="Curation Manual2.0" contentmodel="wikitext" pagelanguage="en" touched="2024-07-18T18:19:41Z" lastrevid="2730" counter="8796533" length="222692" />
      <page pageid="1421" ns="0" title="Data Field Descriptions" contentmodel="wikitext" pagelanguage="en" touched="2023-03-29T18:25:51Z" lastrevid="2598" counter="133748" length="77053" />
      <page pageid="1422" ns="0" title="Disease Specific Rules" contentmodel="wikitext" pagelanguage="en" touched="2022-10-24T16:21:47Z" lastrevid="2562" counter="253348" length="19076" />
      <page pageid="1384" ns="0" title="IEDB Inclusion Criteria" contentmodel="wikitext" pagelanguage="en" touched="2024-02-12T23:21:08Z" lastrevid="2696" counter="109194" length="17486" />
      <page pageid="1423" ns="0" title="Non-peptidic Specific Rules" contentmodel="wikitext" pagelanguage="en" touched="2022-10-24T16:17:57Z" lastrevid="2560" counter="56202" length="7128" />
    </pages>
  </query>
</api>