I think root/etc/mk.conf in nrelease is old cruft not used by pkgsrc
anymore, but I'm not 100% sure w/ regards to non-pkgsrc stuff.
pkgsrc uses /usr/pkg/etc/mk.conf and the nrelease builds them
explicitly in the Makefile (e.g. around line 379 of
/usr/src/nrelease/Makefile).
Here's my take on the licensing issue. We want minimal licenses
for the official ISO and IMG, but we can allow any licenses for the
official GUI build so long as they allow the stuff to be pre-installed.
If need-be we can put a notice on the wiki/web-page with regards to
licenses used in the GUI build. IMHO people who want the GUI stuff
will already be mostly aware of the licensing involved.
-Matt