diff --git a/hgext/patchbomb.py b/hgext/patchbomb.py
--- a/hgext/patchbomb.py
+++ b/hgext/patchbomb.py
@@ -130,6 +130,9 @@ configitem('patchbomb', 'publicurl',
 configitem('patchbomb', 'reply-to',
     default=None,
 )
+configitem('patchbomb', 'to',
+    default=None,
+)
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -314,6 +314,9 @@ coreconfigitem('email', 'method',
 coreconfigitem('email', 'reply-to',
     default=None,
 )
+coreconfigitem('email', 'to',
+    default=None,
+)
 coreconfigitem('experimental', 'archivemetatemplate',
     default=dynamicdefault,
 )