title: "SPDX license identifier not provided" warning - what does it mean?
body: <blockquote>
  <p>Warning: SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing &quot;SPDX-License-Identifier: &quot; to each source file. Use &quot;SPDX-License-Identifier: UNLICENSED&quot; for non-open-source code. Please see <a href="https://spdx.org" rel="nofollow noreferrer">https://spdx.org</a> for more information.</p>
  </blockquote>