The way in which the Atom plug-in framework attempts to match an incoming HTTP request has been changed to help simplify the regular expressions that you define.
The atom plug-in framework now attempts to match an incoming HTTP request to the mapping rules strictly in the order that you define them in the configuration file. As soon as a match is found, the request is routed to the feed in which that feed-mapping element is defined, and the corresponding feed-mapping settings determine how the request is processed. This can help to simplify the regular expressions that you define, because it means that you can safely use more general expressions, that might match several different URIs, provided that you define them after more specific expressions.