diff --git a/tail.1 b/tail.1
index df7210c..1387ae4 100644
--- a/tail.1
+++ b/tail.1
@@ -48,3 +48,8 @@ The
 utility is compliant with the
 .St -p1003.1-2008
 specification.
+.Pp
+The
+.Op Fl N
+flag is an extension to that specification.
+