Has a button called the "Online builder". <select that option>
Down the page, select "Advanced" and out puts a menu of choices.
One is called the "software manifest":
"yes will generate a software manifest with e.g. versions and licenses
of the installed packages"
http://narcissus.angstrom-distribution.org/
That's all I know, but it looks cool and exactly what you were looking for?
Whoever is working on the bug you filed to add some sort of software
listing and corresponding licenses to embedded Gentoo, should take a
look at this page, imho.