I have a hard time understanding the ontology of the properties as appearing in the Wikidata Query Service (WDQS) in connection with the statements. In the nt generated from the wikidata.org website I get:
<http://www.wikidata.org/entity/statement/Q80-f415fcf7-4fec-59f7-7793-e71aa5874323> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://wikiba.se/ontology-beta#Statement> . <http://www.wikidata.org/entity/statement/Q80-f415fcf7-4fec-59f7-7793-e71aa5874323> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://wikiba.se/ontology-beta#BestRank> .
This is in accordance with the documentation at https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format#Statement_types
But using the WDQS with
SELECT ?p1 ?value WHERE { <http://www.wikidata.org/entity/statement/Q80-f415fcf7-4fec-59f7-7793-e71aa5874323> ?p1 ?value . }
I get rdf:type wikibase:BestRank but not wikibase:Statement. I would have expected rdf:type wikibase:Statement too. When I check the data on Wikidata.org it is normal ranked https://www.wikidata.org/wiki/Q80#P734. So furthermore the "best rank" seems strange to me.