where are the docs for $HG environment variable?

[Lee Cantey]

On 7/1/07, Forest <h1brzs702 at sneakemail.com> wrote:
> I just upgraded my windows box to mercurial 0.9.4 from a recent 0.9.3
> snapshot, and found that hgk was broken.  It seems that, despite already
> having the hg executable in my path, I now also have to set the HG
> environment variable for this to work.

I haven't seen this so far with the following steps.  I just installed
hgk by copying  hgk to contrib, tclkit-win32.exe to the root of the
install and make an hgk.cmd file containing "@tclkit-win32.exe
contrib\hgk".  Hopefully that will get you working