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>
    <blocks>
      <block id="6" user="Sami Kaddoura" by="René Quillet" timestamp="2017-07-14T07:10:58Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
      <block id="5" user="Roman Seifert" by="René Quillet" timestamp="2017-07-14T07:10:11Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
      <block id="4" user="Miriam Baumeister" by="René Quillet" timestamp="2017-07-14T07:09:45Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
      <block id="3" user="Manuela Nipp" by="René Quillet" timestamp="2017-07-14T07:09:02Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
      <block id="2" user="Isabel Koellreuter" by="René Quillet" timestamp="2017-07-14T07:07:50Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
      <block id="1" user="Franziska Schürch" by="René Quillet" timestamp="2017-07-14T07:04:52Z" expiry="infinity" reason="Projekt beendet, keine Aktivitäten mehr" nocreate="" autoblock="" />
    </blocks>
  </query>
</api>