Data format version

Was wondering if anyone knew of a predicate that could be used to define
the data format in a document.

It's not the MIME type, more a level of granularity within a mime type to
represent certain evolutions of the project.

I've looked at

owl : versionInfo -- but that seems only to apply to ontologies

doap : version -- but that seems to apply to projects

http://www.w3.org/2000/10/swap/pim/doc#version -- seems to be the version
of the document

What I'm looking for is a string that say the data in the document is of a
certain kind e.g. opensocial v0.1 vs opensocial v0.2

I know RDF should be perfectly self descriptive, but this will give the
processor a hint as to what it will find, any bugs etc.