diff --git a/metropolis/test/e2e/selftest/main.go b/metropolis/test/e2e/selftest/main.go
index 2603eae..3b31c5b 100644
--- a/metropolis/test/e2e/selftest/main.go
+++ b/metropolis/test/e2e/selftest/main.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package main
 
 import (