diff --git a/hgext/show.py b/hgext/show.py
--- a/hgext/show.py
+++ b/hgext/show.py
@@ -51,6 +51,13 @@ testedwith = 'ships-with-hg-core'
 
 cmdtable = {}
 command = registrar.command(cmdtable)
+
+configtable = {}
+configitem = registrar.configitem(configtable)
+configitem('commands', 'show.aliasprefix',
+    default=list,
+)
+
 revsetpredicate = registrar.revsetpredicate()
 
 class showcmdfunc(registrar._funcregistrarbase):