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="328" ns="0" title="Charles Oberthür" />
      <page pageid="105" ns="0" title="E-I" />
      <page pageid="8" ns="0" title="Elias Parish Alvars" />
      <page pageid="6" ns="0" title="François-Joseph Dizi" />
      <page pageid="2" ns="0" title="Harp Music of the 18th and 19th Centuries" />
      <page pageid="102" ns="0" title="J-N" />
      <page pageid="5" ns="0" title="Nicolas-Charles Bochsa" />
      <page pageid="103" ns="0" title="O-S" />
      <page pageid="104" ns="0" title="T-Z" />
    </pages>
  </query>
</api>