This is said in at least 5 good tea books that I've seen; not the books
with the pretty pictures from Taiwan, but the ones that contain more
scientific information about the tea. More and more people are
beginning to say it is not black.

It is an ingredient in "leung cha" which in cantonese translates to
cool tea which is a medicine tea to help cool the blood. The bosses
that don't dabble in pu'er are fools IMHO; the market is becoming
larger and larger and the tea never goes bad! heh.