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>
    <allimages gaicontinue="3_Norwegian_Appendix_plus_3_SLAVOB-final.pdf" />
  </query-continue>
  <query>
    <pages>
      <page pageid="456" ns="6" title="File:1 Introlabels SLAVOB-final.pdf" />
      <page pageid="103" ns="6" title="File:23rdSCL.pdf" />
      <page pageid="2610" ns="6" title="File:13849489334 69055de984-1-.jpg" />
      <page pageid="1072" ns="6" title="File:12032011038.jpg" />
      <page pageid="1874" ns="6" title="File:2.jpg" />
      <page pageid="239" ns="6" title="File:2birds.jpg" />
      <page pageid="1487" ns="6" title="File:010 short sample.wav" />
      <page pageid="457" ns="6" title="File:2 Ga appendix SLAVOB-final.pdf" />
      <page pageid="1736" ns="6" title="File:1.png" />
      <page pageid="2720" ns="6" title="File:2016 SLE Biberauer Emergent features.pdf" />
    </pages>
  </query>
</api>