Bundled license information:

lit-html/async-directive.js:
  /**
   * @license
   * Copyright 2017 Google LLC
   * SPDX-License-Identifier: BSD-3-Clause
   */

lit-html/directives/ref.js:
  /**
   * @license
   * Copyright 2020 Google LLC
   * SPDX-License-Identifier: BSD-3-Clause
   */