Looks like there's a bug in current dumping code - https://test.wikidata.org/wiki/Special:EntityData/Q1226.ttl?flavor=dump has this:
wikibase:Dump a schema:Dataset ; cc:license <http://creativecommons.org/publicdomain/zero/1.0/> ; schema:softwareVersion "0.0.1" ; schema:dateModified "2015-05-06T19:56:34Z"^^xsd:dateTime .
which should only happen in dump, not in Special:EntityData.