Many (but not all) of the add on projects have documentation, often as docbooks.
The "bin" packaging of these typically bundles the results of any docbook processing as html and pdf within the artifact being produced - for example, the PEAR file. The add-on bundle (which serves to combine the "releasable" add-ons as one unit) then just includes the documentation as it appears in each binary bundle, if I recall correctly. There is a not-yet-completely-worked-out set of conventions to also have our web-site automatically updated with new documentation for the addons. For instance, the page http://uima.apache.org/sandbox.html#regex.annotator has a link which says "click here to view the documentation". I think this isn't yet automated, so has to be done by "hand". -Marshall
