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>
    <links plcontinue="691|0|2023_Formula_Sprint_2_season" />
  </query-continue>
  <query>
    <pages>
      <page pageid="691" ns="0" title="Main Page">
        <links>
          <pl ns="0" title="2016 Supercup United States Grand Prix" />
          <pl ns="0" title="2021 Formula Challenge season" />
          <pl ns="0" title="2021 Supercup season" />
          <pl ns="0" title="2021 Superleague Lights season" />
          <pl ns="0" title="2021 Superleague season" />
          <pl ns="0" title="2022 Formula Sprint 1 season" />
          <pl ns="0" title="2022 Formula Sprint 2 season" />
          <pl ns="0" title="2022 Superleague season" />
          <pl ns="0" title="2022 Superlights season" />
          <pl ns="0" title="2023 Formula Sprint 1 season" />
        </links>
      </page>
    </pages>
  </query>
</api>