On 31 Aug 2024, at 18:12, Arthur A. Gleckler <xxxxxx@speechcode.com> wrote:

>> One option would be for an author to put an ‘archival’ version of a sample implementation in the SRFI repository under MIT, and distribute their own version of the library under whatever other licence they choose. In the case of CC0 or other public domain declarations, though, this would amount to a legal lie. As author, I can’t in honesty put a ‘Copyright Daphne Preston-Kendal’ notice, and a requirement to reproduce that notice, on a file which is emphatically not copyrighted at all, because I have elsewhere abandoned the copyright.
>
> If you'd like to use a dual license, that would be fine with me.

My point is that together with a public domain declaration such as CC0, a dual ‘licence’ is not valid, because the MIT licence asserts copyright ownership in the work, which CC0 (or any other statement placing something in the public domain) presumes to have been irrevocably abandoned.

Daphne Preston-Kendal