Per T129046 the following are added:
wdata:Q2 a schema:Dataset ; schema:about wd:Q2 ; wikibase:sitelinks "1"^^xsd:integer ; wikibase:statements "25"^^xsd:integer .
It would be interesting to have an additional statement
wdata:Q2 wikibase:externalids "15"^^xsd:integer
This as external-identifiers are conceptually closer to sitelinks than other statements.
This way we could use it on query.wikidata.org etc ..