--- a/hgext/show.py	Sun Oct 08 20:11:34 2017 +0200
+++ b/hgext/show.py	Sun Oct 08 20:16:09 2017 +0200
@@ -51,6 +51,13 @@
 
 cmdtable = {}
 command = registrar.command(cmdtable)
+
+configtable = {}
+configitem = registrar.configitem(configtable)
+configitem('commands', 'show.aliasprefix',
+    default=list,
+)
+
 revsetpredicate = registrar.revsetpredicate()
 
 class showcmdfunc(registrar._funcregistrarbase):