About: http://webisa.webdatacommons.org/264279070

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	preview all kinds of files so your callback must call the set_preview_widget_active()
http://www.w3.org/ns/prov#wasQuotedFrom	pygtk.org