diff --git a/cmd/backup/exec.go b/cmd/backup/exec.go
index 64c858a..00f1c05 100644
--- a/cmd/backup/exec.go
+++ b/cmd/backup/exec.go
@@ -1,6 +1,9 @@
 // Copyright 2022 - Offen Authors <hioffen@posteo.de>
 // SPDX-License-Identifier: MPL-2.0
 
+// Portions of this file are taken and adapted from `moby`, Copyright 2012-2017 Docker, Inc.
+// Licensed under the Apache 2.0 License: https://github.com/moby/moby/blob/8e610b2b55bfd1bfa9436ab110d311f5e8a74dcb/LICENSE
+
 package main
 
 import (