diff --git a/metropolis/test/launch/prefixed_stdio.go b/metropolis/test/launch/prefixed_stdio.go
index c851c44..2e4bbd2 100644
--- a/metropolis/test/launch/prefixed_stdio.go
+++ b/metropolis/test/launch/prefixed_stdio.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package launch
 
 import (