Question about developers handbook definition of encumbered.

[David Leimbach]

As I am slowly trying to get my feet wet with kernel programming
I was browsing through the developers handbook.

The following surprised me a bit:
http://www.freebsd.org/doc/en_US.ISO8859-1/books/developers-handbook/ 
policies-encumbered.html

So this claims that GNU licensing is *not* encumbered... is this  
correct?  Based
on recent discussion threads on this list I would assume it is not  
correct.

Dave