Re: feedmail.el in the public domain?

[Paul Eggert]

Stefan Monnier wrote:
> 1- Take a file from public domain.
> 2- Make many small changes to it over the course of several years (all
>     after the Berne convention).
> 3- Assume the sum of those changes is significantly higher than the
>     "20-lines triviality threshold".
> 4- Is the result still public domain?

No, the result is public domain only if the contributors deliberately place it 
into the public domain, in a process known as dedication. And that process is 
legally controversial for works created after 1976 in the US - though I'm 
perhaps giving you more detail than you want to know, Creative Commons 
recommends against relying on such dedications 
<https://creativecommons.org/licenses/publicdomain/>.

> If not, then the notice on this file (and others like it) is incorrect
> [ This case better matches my mental model of how copyright law works.  ]

You're right about this.