Hi!
The RDF export, too, is not currently generated by Wikibase. However,
Beta version for Wikidata is already on https://dumps.wikimedia.org/wikidatawiki/entities/ - however note the word "beta" :) That means it is not stable and in the following month or so will undergo some big changes, including ontology changes and others. However, it shows what export capabilities do.
These capabilities can be used by any Wikibase instance by running maintenance/dumpRdf.php or maintenance/dumpJson.php scripts, but - again - these features are not 100% stable yet AFAIK, especially RDF part that has some missing parts (see https://phabricator.wikimedia.org/T50143), though dumpJson should be safe to use if you want JSON. We're actively working on the RDF part so it will be ready for use soon too.