I'll list each category along with a description of the messages it groups together.  The logging topical guide is really user-oriented.  For example, I'll have something like:

* org.hibernate.orm.deprecation - Used to log information about usage of features or settings that should be considered deprecated.  While usage of such features/settings will continue to work as previously expected in the current release, you should fully expect support for them to go away in some future version.
* org.hibernate.orm.url - ...