diff --git a/packages/frontend/lib/vite-plugin-watch-locales.ts b/packages/frontend/lib/vite-plugin-watch-locales.ts
index 4ecc99b8ff..8e209d27bd 100644
--- a/packages/frontend/lib/vite-plugin-watch-locales.ts
+++ b/packages/frontend/lib/vite-plugin-watch-locales.ts
@@ -1,3 +1,8 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
 import path from 'node:path'
 import locales from '../../../locales/index.js';