A new license page shows up for all AS servers being downloaded via the runtime download dialog. Seam runtimes still do not show any license.
You may check
JBIDE-12581 for examples, but basically, each extension making use of the downloadRuntime extension point may also add a licenseUrl="http://some/website/" to find the url of the license.
I am not sure what licenses the various seam runtimes are released under.