The WS-ReliableMessaging plugin documents the wsrm plugin for WS-ReliableMessaging support. Although wsrm uses the wsa plugin for WS-Addressing, there is no need to read the wsa plugin documentation because this part of the documentation is self-contained. WS-Addressing usage is mentioned when applicable.
The WS-Addressing Plugin documents the wsa plugin for WS-Addressing (2003/2004/2005 standards) support. The wsa plugin is used by the wsrm plugin.