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OS Workflow: https://svn.java.net/svn/osworkflow~svn/tags/osworkflow_2-8-0/
OS Core: http://svn.opensymphony.com/svn/oscore/tags/oscore_2_2_5/ and http://svn.opensymphony.com/svn/oscore/tags/oscore_2_2_7/
Property Set: http://svn.opensymphony.com/svn/propertyset/tags/propertyset-1.4 and - note, osworkflow 2.8.0 uses propertyset 1.5 not 1.4
A new source repository has appeared at http://svnrepository.opensymphony.com/svn/propertyset/tags/opencastproject.org/nexus/content/repositories/public/opensymphony/. I was able to get the propertyset-1.5 code from here.
Javadoc
I found Javadoc here:
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