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="1" ns="0" title="Main Page">
        <links>
          <pl ns="0" title="Autumn Semester 2017" />
          <pl ns="0" title="Autumn Semester 2018" />
          <pl ns="0" title="Autumn Semester 2019" />
          <pl ns="0" title="Autumn Semester 2020" />
          <pl ns="0" title="Spring Semester 2015" />
          <pl ns="0" title="Spring Semester 2016" />
          <pl ns="0" title="Spring Semester 2017" />
          <pl ns="0" title="Spring Semester 2018" />
          <pl ns="0" title="Spring Semester 2019" />
          <pl ns="0" title="Spring Semester 2020" />
        </links>
      </page>
    </pages>
  </query>
</api>