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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.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allredirects arcontinue="Guide_to_GEOS-Chem_error_messages" />
  </query-continue>
  <query>
    <allredirects>
      <r ns="0" title="Compiling with CMake" />
      <r ns="0" title="Developing GEOS-Chem" />
      <r ns="0" title="Emissions Working Group" />
      <r ns="0" title="GEOS-Chem 12" />
      <r ns="0" title="GEOS-Chem 12 benchmark history" />
      <r ns="0" title="GEOS-Chem 13.0.0" />
      <r ns="0" title="GEOS-Chem Support Team" />
      <r ns="0" title="GEOS-Chem output files" />
      <r ns="0" title="GEOS-Chem versions" />
      <r ns="0" title="Guide to GEOS-Chem History diagnostics" />
    </allredirects>
  </query>
</api>