diff --git a/compat/regex/intprops.h b/compat/regex/intprops.h
index 716741adc5..2aef98d290 100644
--- a/compat/regex/intprops.h
+++ b/compat/regex/intprops.h
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* intprops.h -- properties of integer types

    Copyright (C) 2001-2016 Free Software Foundation, Inc.
diff --git a/compat/regex/regcomp.c b/compat/regex/regcomp.c
index 5ac5370142..a1fb2e400e 100644
--- a/compat/regex/regcomp.c
+++ b/compat/regex/regcomp.c
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Extended regular expression matching and search library.
    Copyright (C) 2002-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
diff --git a/compat/regex/regex.c b/compat/regex/regex.c
index 9f133fab84..d6e525e567 100644
--- a/compat/regex/regex.c
+++ b/compat/regex/regex.c
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Extended regular expression matching and search library.
    Copyright (C) 2002-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
diff --git a/compat/regex/regex.h b/compat/regex/regex.h
index 143b3afa89..b602b5567f 100644
--- a/compat/regex/regex.h
+++ b/compat/regex/regex.h
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Definitions for data structures and routines for the regular
    expression library.
    Copyright (C) 1985, 1989-2016 Free Software Foundation, Inc.
diff --git a/compat/regex/regex_internal.c b/compat/regex/regex_internal.c
index 18641ef1c0..6d766114a1 100644
--- a/compat/regex/regex_internal.c
+++ b/compat/regex/regex_internal.c
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Extended regular expression matching and search library.
    Copyright (C) 2002-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
diff --git a/compat/regex/regex_internal.h b/compat/regex/regex_internal.h
index 01465e7678..9c88a6a57b 100644
--- a/compat/regex/regex_internal.h
+++ b/compat/regex/regex_internal.h
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Extended regular expression matching and search library.
    Copyright (C) 2002-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
diff --git a/compat/regex/regexec.c b/compat/regex/regexec.c
index c8f11e52e7..c79ff38b1c 100644
--- a/compat/regex/regexec.c
+++ b/compat/regex/regexec.c
@@ -1,3 +1,10 @@
+/*
+ * This is git.git's copy of gawk.git's regex engine. Please see that
+ * project for the latest version & to submit patches to this code,
+ * and git.git's compat/regex/README for information on how git's copy
+ * of this code is maintained.
+ */
+
 /* Extended regular expression matching and search library.
    Copyright (C) 2002-2016 Free Software Foundation, Inc.
    This file is part of the GNU C Library.