Google is getting ready for the next stage of Docs, at least the file storage part, its transformation into Google Drive. While Google hasn't confirmed the move, there have been to many signs and actual proof to doubt that Drive is coming and coming soon.
In a move that perhaps indicates that Drive will become the universal storage service for Google, some users are now seeing Google Sites data in Google Docs, as Google Operating System
noted.
Google may have been preparing or at least thinking about this for at least several months, but is now making the first moves.
Whether this is just a solitary test, or part of a broader roll out remains to be seen. It seems clear though that Google Drive along with the very anticipated Drive desktop app are coming soon.