@serenesurface-- As far as I know, all rye breads are considered brown breads although the ratio of rye flour might be important. If a bread is made with a high ratio of brown flour such as whole wheat flour or rye flour, then it's brown bread.
Pumpernickle is made completely with rye flour. I think some are also made with rye berries which is why the bread is very dark. The pumpernickle breads I've seen were the same color as chocolate!