diff --git a/hgext/show.py b/hgext/show.py
--- a/hgext/show.py
+++ b/hgext/show.py
@@ -52,12 +52,6 @@
 cmdtable = {}
 command = registrar.command(cmdtable)
 
-configtable = {}
-configitem = registrar.configitem(configtable)
-configitem('commands', 'show.aliasprefix',
-    default=list,
-)
-
 revsetpredicate = registrar.revsetpredicate()
 
 class showcmdfunc(registrar._funcregistrarbase):
diff --git a/mercurial/configitems.py b/mercurial/configitems.py
--- a/mercurial/configitems.py
+++ b/mercurial/configitems.py
@@ -170,6 +170,9 @@
 coreconfigitem('color', 'pagermode',
     default=dynamicdefault,
 )
+coreconfigitem('commands', 'show.aliasprefix',
+    default=list,
+)
 coreconfigitem('commands', 'status.relative',
     default=False,
 )