Yes, xstreamline3-3.1.1.war is built from inside eclipse,. But it doen't contain the seam jar.
The seam jar is in the local maven repository like all the jars.
It's difficult to reduce it because it has a lot of code and other stuff.
What I would like to know is why the plugin is copying the seam.jar inside the war. There ir no setting or configuration in order to do that.
How does it work? I mean, when the plugin publishes all the code, how does it handle the EJB module declared in the application.xml? Does it copy the file according to some rule or it looks at the application.xml?