The license referred to in the pkg-descr file for graphics/graphviz is not available at the location mentioned. A link on the graphviz website suggests that the correct license is available at a different URL. How-To-Repeat: cat /usr/ports/graphics/graphviz/pkg-descr (follow link to license which 404s).
Responsible Changed From-To: freebsd-ports-bugs->perky Assign to maintainer.
State Changed From-To: open->closed Fixed. Thank you!