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="4" ns="0" title="Extensible Common Software Graph" contentmodel="wikitext" pagelanguage="en" touched="2015-01-22T17:33:00Z" lastrevid="1554" counter="" length="4752" />
      <page pageid="477" ns="0" title="Latest Release" contentmodel="wikitext" pagelanguage="en" touched="2021-11-23T17:13:58Z" lastrevid="2569" counter="" length="27" redirect="" />
      <page pageid="426" ns="0" title="Learning Atlas" contentmodel="wikitext" pagelanguage="en" touched="2015-10-15T20:23:38Z" lastrevid="2094" counter="" length="2564" />
      <page pageid="705" ns="0" title="Learning Atlas for C" contentmodel="wikitext" pagelanguage="en" touched="2017-06-22T21:37:15Z" lastrevid="2493" counter="" length="21752" />
      <page pageid="20" ns="0" title="Using the Atlas Shell" contentmodel="wikitext" pagelanguage="en" touched="2020-05-05T17:45:02Z" lastrevid="2547" counter="" length="29380" />
    </pages>
  </query>
</api>