diff --git a/hgmerge b/hgmerge
--- a/hgmerge
+++ b/hgmerge
@@ -3,10 +3,10 @@
 # hgmerge - default merge helper for Mercurial
 #
 # This tries to find a way to do three-way merge on the current system.
-# The result ought to end up in $1.
+# The result ought to end up in $1.  Script is run in root directory of
+# repository.
 #
 # Environment variables set by Mercurial:
-# HG_ROOT            repo root
 # HG_FILE            name of file within repo
 # HG_MY_NODE         revision being merged
 # HG_OTHER_NODE      revision being merged