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>
    <alltransclusions gatcontinue="Contact_Details|9616" />
  </query-continue>
  <query>
    <pages>
      <page pageid="9100" missing="" />
      <page pageid="9606" ns="0" title="Atlantis Diving Center Volos Sporades Islands" />
      <page pageid="9607" ns="0" title="Atlantis Diving Center Sithonia North East Aegean" />
      <page pageid="9608" ns="0" title="Athos Scuba Aristotelis North East Aegean" />
      <page pageid="9609" ns="0" title="Aquatic Scuba Diving Club Kefalonia Ionian Islands" />
      <page pageid="9610" ns="0" title="Aqualand Sithonia North East Aegean" />
      <page pageid="9612" ns="0" title="Anastasios Papanikolaou Preveza Ionian Islands" />
      <page pageid="9614" ns="0" title="ALMA Diving Center Aristotelis North East Aegean" />
      <page pageid="9615" ns="0" title="Aegean Diving College Paros Cyclades" />
      <page pageid="11259" ns="0" title="CROSTACEO Dive Centre Loutraki Corinthian Gulf" />
    </pages>
  </query>
</api>