From the webpage:
PLUS is a system for capturing and managing provenance information, originally created at the MITRE Corporation.
Data provenance is “information that helps determine the derivation history of a data product…[It includes] the ancestral data product(s) from which this data product evolved, and the process of transformation of these ancestral data product(s).”
Uses Neo4j for storage.
Includes an academic bibliography of related papers.
Provenance answers the question: Where has your data been, what has happened to your data and with who?