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>
    <allfileusages gafcontinue="BookSubbaro.png|1144" />
  </query-continue>
  <query>
    <pages>
      <page pageid="2637" ns="0" title="4th International Endangered and Lesser-known Languages Conference" />
      <page pageid="1682" ns="0" title="Future in Brazilian Portuguese" />
      <page pageid="83" ns="0" title="About Lule Sami" />
      <page pageid="1195" ns="0" title="Preterite/Past tense in Norwegian" />
      <page pageid="376" ns="2" title="User:Ben Waldron" />
      <page pageid="277" ns="0" title="Advisory Board" />
      <page pageid="1232" ns="2" title="User:Deo Kawalya" />
      <page pageid="2587" ns="0" title="Notions of &#039;feature&#039; in linguistic theory: cross-theoretical and cross-linguistic perspectives" />
      <page pageid="53" ns="14" title="Category:Community Portal" />
      <page pageid="287" ns="2" title="User:Misah Natumanya" />
    </pages>
  </query>
</api>