diff -pruN2 mutt-1.3.24.orig/doc/manual.sgml.head mutt-1.3.24/doc/manual.sgml.head
--- mutt-1.3.24.orig/doc/manual.sgml.head	Tue Nov  6 11:34:04 2001
+++ mutt-1.3.24/doc/manual.sgml.head	Sat Jan 19 21:36:37 2002
@@ -1719,4 +1719,5 @@ messages:
 ~y EXPR         messages which contain EXPR in the `X-Label' field
 ~z [MIN]-[MAX]  messages with a size in the range MIN to MAX *)
+~=		duplicated messages (see $duplicate_threads)
 </verb></tscreen>
 
diff -pruN2 mutt-1.3.24.orig/mutt.h mutt-1.3.24/mutt.h
--- mutt-1.3.24.orig/mutt.h	Thu Nov  8 18:35:13 2001
+++ mutt-1.3.24/mutt.h	Sat Jan 19 21:36:37 2002
@@ -200,4 +200,5 @@ enum
   M_DATE,
   M_DATE_RECEIVED,
+  M_DUPLICATED,
   M_ID,
   M_BODY,
diff -pruN2 mutt-1.3.24.orig/pattern.c mutt-1.3.24/pattern.c
--- mutt-1.3.24.orig/pattern.c	Thu Apr 26 15:36:34 2001
+++ mutt-1.3.24/pattern.c	Sat Jan 19 21:36:37 2002
@@ -91,4 +91,5 @@ Flags[] =
   { 'y', M_XLABEL,		0,		eat_regexp },
   { 'z', M_SIZE,		0,		eat_range },
+  { '=', M_DUPLICATED,		0,		NULL },
   { 0 }
 };
@@ -1051,4 +1052,6 @@ mutt_pattern_exec (struct pattern_t *pat
     case M_XLABEL:
       return (pat->not ^ (h->env->x_label && regexec (pat->rx, h->env->x_label, 0, NULL, 0) == 0));
+    case M_DUPLICATED:
+      return (pat->not ^ (h->thread && h->thread->duplicate_thread));
   }
   mutt_error (_("error: unknown op %d (report this error)."), pat->op);
diff -pruN mutt-1.3.24.orig/PATCHES mutt-1.3.24/PATCHES
--- mutt-1.3.24.orig/PATCHES    Mon Nov 26 20:16:52 2001
+++ mutt-1.3.24/PATCHES Thu Dec  6 16:27:55 2001
@@ -1,0 +1 @@
+patch-1.3.24.cd.pattern_duplicates.1