Development:  Bugs in the development process, such as a misconfigured CVS or Bugzilla installation, insufficient development proceses, or malfunctioning developers.
PG:  The PG system, including the PG translator, modules, and macro files.
Problem libraries:  Problems contained in problem libraries hosted by the WeBWorK project.
TestProduct:  This is a test product. This ought to be blown away and replaced with real stuff in a finished installation of bugzilla.
WeBWorK:  The WeBWorK 1.x series.
WeBWorK 2:  The WeBWorK 2.x series.
wwassignment:  Moodle module, written in php, which allows webwork assignments to appear within moodle.