About: http://webisa.webdatacommons.org/300932088

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	NSTX is the most likely candidate since it is not likely the organization with the captive portal prevents access to the DNS proxy/server you are using to resolve the captive portal name.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com