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>
    <allredirects garcontinue="Henri_Champs_(1887-1915)|5039" />
  </query-continue>
  <query>
    <pages>
      <page pageid="4749" ns="0" title="Gabriel Fernand Thillo (1882-1915)" />
      <page pageid="4878" ns="0" title="Frédéric Alexandre Rasse (1890-1915)" />
      <page pageid="4914" ns="0" title="Edouard Léon Achille Ribière (1894-1916)" />
      <page pageid="4920" ns="0" title="Gustave Léon Lerondeau (1872-1916)" />
      <page pageid="4922" ns="0" title="François Portrat (1887-1916)" />
      <page pageid="4927" ns="0" title="François Henri Eelbo (1879-1915)" />
      <page pageid="4942" ns="0" title="Georges Boulanger (1893-1918)" />
      <page pageid="4969" ns="0" title="Charles Thierry (1891-1918)" />
      <page pageid="5068" ns="0" title="Edouard Jean Texier (-1915)" />
      <page pageid="5074" ns="0" title="Félix Edouard Macquart (1892-1916)" />
    </pages>
  </query>
</api>