license change policy for patches added for ports?

[Jeremy C. Reed]

I am curious about if FreeBSD has a policy on licenses for patches added 
to ports?

I am looking through the FreeBSD Porter's handbook and don't see anything 
mentioned yet. 

http://www.freebsd.org/doc/en_US.ISO8859-1/books/porters-handbook/slow-patch.html 
doesn't mention licensing.

The port where I have heard complaints about is the added copyright to
ports/audio/cdparanoia

Any comments? Any policy?

One idea would be that anything added to FreeBSD ports files patches should 
need to be under the same original license. But I understand there could 
be exceptions.

Mostly I am just curious.

  Jeremy C. Reed