XSD

You can validate and use content assist for the XML configuration using this namespace declaration:

<?xml version="1.0" encoding="UTF-8"?>
<jmapper
   xmlns="http://jmapper-framework.github.io" 
   xmlns:xsi="http://jmapper-framework.github.io/jmapper-core" 
   xsi:noNamespaceSchemaLocation="http://jmapper-framework.github.io/jmapper-core/jmapper-1.6.0.xsd"/>
</jmapper>

XML Schema

if you want to see the contents of the file click on this link.