On Special:RecentChanges, the parameter "namespace" filters the results. However, when feed=rss is used, the namespace parameter is ignored.
Bug is present in 1.16alpha-wmf (r59133) on Wikipedia, as well as 1.15.1.
Case study:
Uses namespace:
http://en.wikipedia.org/wiki/Special:RecentChanges?namespace=2
Ignores namespace (bug):
http://en.wikipedia.org/wiki/Special:RecentChanges?namespace=2&feed=rss
Version: 1.16.x
Severity: normal