What does `brew man` do? I mean brew man, not man brew.

It says:


  Fetching: hpricot-0.8.6.gem (100%) Building native extensions.  This
  could take a while... Successfully installed hpricot-0.8.6 Fetching:
  rdiscount-2.1.8.gem (100%) Building native extensions.  This could
  take a while... Successfully installed rdiscount-2.1.8 Fetching:
  mustache-1.0.1.gem (100%) Successfully installed mustache-1.0.1
  Fetching: ronn-0.7.3.gem (100%) Successfully installed ronn-0.7.3 4
  gems installed Writing manpages to /usr/local/share/man/man1


So what have I installed? What does it do?
From Homebrew issue #40735, what would the command "brew man cask" do? (which can be found by simply googling "brew man")


  brew man generates the Homebrew manpage from markdown, using these gems to do the translation.