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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.
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<?xml version="1.0"?>
<api>
  <query-continue>
    <allpages apcontinue="LaTeX/Mathematics" />
  </query-continue>
  <query>
    <allpages>
      <p pageid="9" ns="0" title="LaTeX" />
      <p pageid="13" ns="0" title="LaTeX/Basics" />
      <p pageid="31" ns="0" title="LaTeX/Bibliography Management" />
      <p pageid="28" ns="0" title="LaTeX/Dessiner avec LaTeX/Dessiner avec PGF et TikZ" />
      <p pageid="38" ns="0" title="LaTeX/Errors and Warnings" />
      <p pageid="7" ns="0" title="LaTeX/Généralités" />
      <p pageid="40" ns="0" title="LaTeX/Importing Graphics" />
      <p pageid="51" ns="0" title="LaTeX/Installation" />
      <p pageid="36" ns="0" title="LaTeX/Introduction" />
      <p pageid="39" ns="0" title="LaTeX/List Structures" />
    </allpages>
  </query>
</api>