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>
    <namespaces>
      <ns id="-2" case="first-letter" canonical="Media" xml:space="preserve">Media</ns>
      <ns id="-1" case="first-letter" canonical="Special" xml:space="preserve">Special</ns>
      <ns id="0" case="first-letter" subpages="" content="" xml:space="preserve" />
      <ns id="1" case="first-letter" subpages="" canonical="Talk" xml:space="preserve">Talk</ns>
      <ns id="2" case="first-letter" subpages="" canonical="User" xml:space="preserve">User</ns>
      <ns id="3" case="first-letter" subpages="" canonical="User talk" xml:space="preserve">User talk</ns>
      <ns id="4" case="first-letter" subpages="" canonical="Project" xml:space="preserve">Project</ns>
      <ns id="5" case="first-letter" subpages="" canonical="Project talk" xml:space="preserve">Project talk</ns>
      <ns id="6" case="first-letter" subpages="" canonical="File" xml:space="preserve">File</ns>
      <ns id="7" case="first-letter" subpages="" canonical="File talk" xml:space="preserve">File talk</ns>
      <ns id="8" case="first-letter" subpages="" canonical="MediaWiki" xml:space="preserve">MediaWiki</ns>
      <ns id="9" case="first-letter" subpages="" canonical="MediaWiki talk" xml:space="preserve">MediaWiki talk</ns>
      <ns id="10" case="first-letter" subpages="" canonical="Template" xml:space="preserve">Template</ns>
      <ns id="11" case="first-letter" subpages="" canonical="Template talk" xml:space="preserve">Template talk</ns>
      <ns id="12" case="first-letter" subpages="" canonical="Help" xml:space="preserve">Help</ns>
      <ns id="13" case="first-letter" subpages="" canonical="Help talk" xml:space="preserve">Help talk</ns>
      <ns id="14" case="first-letter" subpages="" canonical="Category" xml:space="preserve">Category</ns>
      <ns id="15" case="first-letter" subpages="" canonical="Category talk" xml:space="preserve">Category talk</ns>
      <ns id="100" case="first-letter" subpages="" canonical="Linden Lab Official" content="" xml:space="preserve">Linden Lab Official</ns>
      <ns id="101" case="first-letter" subpages="" canonical="Linden Lab Official talk" xml:space="preserve">Linden Lab Official talk</ns>
      <ns id="102" case="first-letter" subpages="" canonical="Viewerhelp" xml:space="preserve">Viewerhelp</ns>
      <ns id="103" case="first-letter" subpages="" canonical="Viewerhelp talk" xml:space="preserve">Viewerhelp talk</ns>
      <ns id="104" case="first-letter" subpages="" canonical="Article officiel de Linden Lab" xml:space="preserve">Article officiel de Linden Lab</ns>
      <ns id="105" case="first-letter" subpages="" canonical="Article officiel de Linden Lab talk" xml:space="preserve">Article officiel de Linden Lab talk</ns>
      <ns id="106" case="first-letter" subpages="" canonical="Linden Lab公認" xml:space="preserve">Linden Lab公認</ns>
      <ns id="107" case="first-letter" subpages="" canonical="Linden Lab公認 talk" xml:space="preserve">Linden Lab公認 talk</ns>
      <ns id="108" case="first-letter" subpages="" canonical="Articolo ufficiale Linden Lab" xml:space="preserve">Articolo ufficiale Linden Lab</ns>
      <ns id="109" case="first-letter" subpages="" canonical="Articolo ufficiale Linden Lab talk" xml:space="preserve">Articolo ufficiale Linden Lab talk</ns>
      <ns id="110" case="first-letter" subpages="" canonical="Artigo oficial da Linden Lab" xml:space="preserve">Artigo oficial da Linden Lab</ns>
      <ns id="111" case="first-letter" subpages="" canonical="Artigo oficial da Linden Lab talk" xml:space="preserve">Artigo oficial da Linden Lab talk</ns>
      <ns id="112" case="first-letter" subpages="" canonical="Artículo oficial de Linden Lab" xml:space="preserve">Artículo oficial de Linden Lab</ns>
      <ns id="113" case="first-letter" subpages="" canonical="Artículo oficial de Linden Lab talk" xml:space="preserve">Artículo oficial de Linden Lab talk</ns>
      <ns id="114" case="first-letter" subpages="" canonical="Linden Lab Offiziell" xml:space="preserve">Linden Lab Offiziell</ns>
      <ns id="115" case="first-letter" subpages="" canonical="Linden Lab Offiziell talk" xml:space="preserve">Linden Lab Offiziell talk</ns>
      <ns id="274" case="first-letter" canonical="Widget" xml:space="preserve">Widget</ns>
      <ns id="275" case="first-letter" canonical="Widget talk" xml:space="preserve">Widget talk</ns>
    </namespaces>
  </query>
</api>