The folder ExportXML contains the XML files which will be used by just:in Engine to create the output Sidecar XML files.
This figure shows how the StartUpXML and the ExportXML templates correlate to each other.
Each <control> node of the StartUpXML contains a <name> node which must to be represented in the ExportXML template.
Each <name> node contains a placeholder for the actual data which is entered in the Metadata fields in the Inspector if just:in. just:in Engine will output the Sidecar XML file with the corresponding data.