Seems to have silently moved to http://ros.org/doc/groovy/changelogs/actionlib/changelog.html
Contents
1.8.4 (2012-04-05)
- Added missing axserver/axclient install
1.8.3 (2012-03-15)
Fixed issue with locking in action server. <<Ticket(ros-pkg 5391)>>
1.8.2 (2012-02-29)
- Catkin update
1.8.1 (2012-02-21)
- Major bug fix for catkin+python packaging
1.8.0 (2012-02-07)
- Separated from common stack, converted to use catkin