Watson Explorer Engine relies exclusively on XML for all configuration files. Many advanced functions can only be performed through XML.
If you are not familiar with XML, the Tutorial: XML Input Format tutorial can give you a quick overview of the XML syntax. We would nevertheless suggest that you read more thorough resources elsewhere on the web.
The ultimate reference for the Watson Explorer XML is the schema documentation (if you do not know what a schema is, see the W3C XML schema primer). The VXML converter functions used by Watson Explorer Engine are stored in the Watson Explorer Engine repository. Because these all begin with the prefix "vse-converter", you can search for information on them like any other repository component.
Data to be clustered is specified using document elements that contain any number of content elements which describe both clusterable and non-clusterable content. After clustering, the data is organized into a tree element which in turn contains document and node elements.
Data to be clustered can also be retrieved using the meta-search capabilities of Watson Explorer Engine. Meta-search connectors are described using source elements associated with forms (which describe how to send a query to the remote source) and parsers (which describe how to parse the content of the remote source). The actual query submission is done through a submit element, which uses the form to convert the user query into a list of parse elements, which are remote requests whose content will be parsed.
Complete documentation for the schema used by Watson Explorer Engine is available online in the Watson Explorer Engine administration tool.