diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
index 12dbdd348bb0977366200bf96cb6d2afa85faf13_bWVyY3VyaWFsL2hlbHAvY29uZmlnLnR4dA==..9d88916fb56f2974717f0856caf907ef41ec66c3_bWVyY3VyaWFsL2hlbHAvY29uZmlnLnR4dA== 100644
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -85,6 +85,9 @@
     be read.  Mercurial checks each of these locations in the specified
     order until one or more configuration files are detected.
 
+.. note:: The registry key ``HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mercurial``
+   is used when running 32-bit Python on 64-bit Windows.
+
 Syntax
 ======