|[higgins-dev] Extending the persona vocabulary|
If you wish to work on extending the Higgins vocabularies, the first step would be to load persona.owl from the SVN (details) and these files into an OWL ontology editor. I'd recommend the free version of TopQuadrant Composer from TopBraid.com.
Since you're not (yet) an Eclipse Higgins committer, you'll only be able to contribute patches, etc. But at least this way you'll be able to load the vocabularies we already have and look around.
BTW, the files in the SVN are the ones to use because the ones listed on each vocabulary wiki page under "most recently published" versions are usually old and out of date.