These are used
as placeholders for the meta-values "unknown value" and
"no value" aren't they ?
Oh, right! I had not considered it to be possible that any subclass of
statement would use "unknown value". All classes could at least be
Yes, bnodes are unknown values. It is kind of weird to have one in P279
since most things with unknown classes just do not have any class, so I
would say it is a kind of data error unless there's a really good
explanation behind it. But from the RDF/SPARQL point of view it's
producing what it supposed to, just in a weird place.
"no value" is different though - it would be "a wdno:P279" in this
Which would say "this item is not subclass of any class whatsoever"
which also sounds kind of strange to me, but maybe there are reasons for
subclasses of "Entity" if nothing else can
be said about them. For some
of the cases in the list I found, it is also unclear why they should be
classes at all.
Every item in RDF dump does have "a wikibase:Item" triple. But in SPARQL
store we drop it since pretty much everything has it so querying by it
is useless and 19M of such triples just sit there and take space.