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>
    <pageswithprop pwpcontinue="3126" />
  </query-continue>
  <query>
    <pageswithprop>
      <page pageid="1053" ns="0" title="ES" value="Wiki de Apache OpenOffice en Español" />
      <page pageid="1689" ns="0" title="DE/Stammtische" value="OpenOffice.org Stammtische" />
      <page pageid="1911" ns="14" title="Category:Art" value="Art Category" />
      <page pageid="2606" ns="0" title="Extensions Packager" value="Extensions Packagers" />
      <page pageid="3100" ns="0" title="Documentation" value="The Apache OpenOffice Documentation Project" />
      <page pageid="3102" ns="0" title="Documentation/FAQ/General" value="General Questions" />
      <page pageid="3106" ns="0" title="Documentation/FAQ/Installation" value="Installation FAQ" />
      <page pageid="3107" ns="0" title="Documentation/FAQ/Writer" value="Apache OpenOffice Writer FAQ" />
      <page pageid="3121" ns="0" title="Documentation/FAQ/Calc" value="Apache OpenOffice Calc FAQ" />
      <page pageid="3125" ns="0" title="Documentation/FAQ/Draw" value="Apache OpenOffice Draw FAQ" />
    </pageswithprop>
  </query>
</api>