When using multiple repositories, it is often useful to blacklist problematic packages, or to whitelist packages to be allowed from a particular repo.  This functionality is provided by the 'includepkgs' and 'exclude' options within a repository directive.  

For example, one could whitelist packages from updates-testing that they use regularly and want to participating testing for, without bringing all testing packages in when updating.

I think it would be helpful to users to document these features in section 4.3.2. Setting [repository] Options .

--Pete