Field Definitions are Available Here
Collection
string (80)
The version of an input collection and/or a dependent collection that is somehow associated with this collection.
5.2.0
/VersionId
/gmi:MI_Metadata/gmd:identificationInfo/gmd:MD_DataIdentification/gmd:citation/gmd:CI_Citation/gmd:edition/gco:CharacterString
Identification Information (ECHO)