diff --git a/packages/backend/migration/js/migration-config.js b/packages/backend/migration/js/migration-config.js
index 5a718fa66c..8cfbb21470 100644
--- a/packages/backend/migration/js/migration-config.js
+++ b/packages/backend/migration/js/migration-config.js
@@ -1,3 +1,7 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
 
 export function isConcurrentIndexMigrationEnabled() {
 	return process.env.MISSKEY_MIGRATION_CREATE_INDEX_CONCURRENTLY === '1';