diff --git a/version/version.go b/version/version.go
index 668e0fa..999854e 100644
--- a/version/version.go
+++ b/version/version.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 // Package version is a companion library to the //version/spec proto.
 package version