diff -r 8c3d449ecc63 -r 849f011dbf79 mercurial/help.py
--- a/mercurial/help.py	Sat Jun 23 12:05:00 2007 +0200
+++ b/mercurial/help.py	Sat Jun 23 20:21:10 2007 +0200
@@ -37,6 +37,11 @@
 
     'environment|env|Environment Variables':
     r'''
+HG::
+    Path to the 'hg' executable, automatically passed when running hooks
+    or external tools. Falls back to 'hg' if unset and the value can't be
+    autodetected, e.g. when Mercurial is run as a Python module.
+
 HGEDITOR::
     This is the name of the editor to use when committing. Defaults to the
     value of EDITOR.