[cutemonster]

> it is still a derived work as it was progressively changed.

I think that depends. If it was progressively changed to something completely different, then, no.

Let's say in 10 days you replaced 10% of the code, with the same amount of code from a different program by another author. During those 10 days there'd be compilation errors, and thereafter the original work and copyright would be all gone (except for in old revisions in the repo), and the copyright holder of the new program could license it however s/he wanted.

[hakre]

It is still likely a derived work. Looks more to me in the example it was just practised the right to make changes to the original work which one could do under the given circumstances which is normally a reciprocal license - floss or else - which means even when if 100% of all letters in all files have been changed, one could still not do more than the original license granted.

and that is normally _not_ what you wrote:

> the copyright holder [sic!] of the new program could license it however s/he wanted.

However if sole copyright holder - real, not imagined - she sure can license it - or not. Or different another day.