About: http://webisa.webdatacommons.org/431267178

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	So the distinction is an artificial one, no doubt useful in the applications being considered in your source (you have to begin somewhere, let's choose the leading variable to eliminate).
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com