CIME includes a number of XML files used for configuration of a case. General Users should never need to modify the XML files in the CIMEROOT. Modifcations to XML settings is case specific and the tools :ref:`xmlquery` and :ref:`xmlchange` in every CASEROOT can be used to query and modify these settings while ensuring the continued schema integrity of the XML.

For advanced CIME developers, there are XML schema definition files in the CIMEROOT/config/xml_schemas directory that can be used with xmllint to verify the XML.