diff --git a/checktab.awk b/checktab.awk
index 9006e9f..0d001b5 100644
--- a/checktab.awk
+++ b/checktab.awk
@@ -1,5 +1,7 @@
 # Check tz tables for consistency.
 
+# %W%
+
 # Contributed by Paul Eggert <eggert@twinsun.com>.
 
 BEGIN {