note that ${foo//bar/baz} may need the pattern escaped; discovered by me

for # and %, and by Matt Lewandowsky («lewellyn:#ksh») for & as pattern.

mksh.1

@@ -1,4 +1,4 @@
-.\" $MirOS: src/bin/mksh/mksh.1,v 1.170 2009/06/21 15:43:17 tg Exp $
+.\" $MirOS: src/bin/mksh/mksh.1,v 1.171 2009/07/06 09:37:03 tg Exp $
 .\" $OpenBSD: ksh.1,v 1.129 2009/05/28 06:09:06 jmc Exp $
 .\"-
 .\" Copyright © 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
@@ -48,7 +48,7 @@
 .el .xD \\$1 \\$2 \\$3 \\$4 \\$5 \\$6 \\$7 \\$8
 ..
 .\"-
-.Dd $Mdocdate: June 21 2009 $
+.Dd $Mdocdate: July 6 2009 $
 .Dt MKSH 1
 .Os MirBSD
 .Sh NAME
@@ -1357,6 +1357,15 @@ Currently,
 must start with a space, opening parenthesis or digit to be recognised.
 .El
 .Pp
+Note that
+.Ar pattern
+may need to be escaped as an extended globbing pattern
+.Pq @(...) ,
+with single quotes
+.Pq \&'...\&'
+or double quotes
+.Pq \&"...\&" .
+.Pp
 The following special parameters are implicitly set by the shell and cannot be
 set directly using assignments:
 .Bl -tag -width "1 ... 9"
@@ -2985,7 +2994,7 @@ This command is usually accessed with the predefined
 .Ic alias r=\*(aqfc \-e \-\*(aq
 or by prefixing an interactive mode input line with
 .Sq \&!
-.Pq extension .
+.Pq wbx extension .
 .Pp
 .It Ic fg Op Ar job ...
 Resume the specified job(s) in the foreground.