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="1350" ns="0" title="Corruption of syslogs (dbcc rebuild log)" />
      <page pageid="1284" ns="0" title="Fixing system tables in the master database after a change of Characterset / SortOrder" />
      <page pageid="1419" ns="0" title="Installation guidelines ASE 15.7" />
      <page pageid="1354" ns="0" title="Installation guidelines IQ 12.6 and 12.7" />
      <page pageid="1310" ns="0" title="Sybase on linux-distro matrix" />
      <page pageid="1301" ns="0" title="WebServices ASE" />
      <page pageid="1308" ns="0" title="Xen" />
    </pages>
  </query>
</api>