Parsed documentation:
View on GitHub
taxonID (http://rs.tdwg.org/dwc/terms/taxonID)

@return [String]
The first field in the data file should be the taxonID representing the
taxon in the core data file to which this vernacular name points. This
identifier provides the link between the core data record and the
extension record.
Please help! Open an issue on GitHub if this assessment is incorrect.