diff --git a/components/util/tid.rs b/components/util/tid.rs
index fdd9a775bcd..22fc3402dfb 100644
--- a/components/util/tid.rs
+++ b/components/util/tid.rs
@@ -1,3 +1,7 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
 use std::sync::atomics::{AtomicUint, INIT_ATOMIC_UINT, SeqCst};
 
 static mut next_tid: AtomicUint = INIT_ATOMIC_UINT;