Today in the p2 call, someone from buckminster
(sorry, didn't catch who) mentioned that they generate categories from
features using some properties in the build.properties file.
Unless I'm missing something, the only
difference in the metadata between a feature group IU and a category is
the property "org.eclipse.equinox.p2.type.category = true".
What this really means, is that with
today's publisher, any feature can be used to generate a category simply
be adding a p2.inf file with the following: