I (Nicolas Casalini), gladly accepts contributions to the engine code either
bugfixes or new features (although I feel no obligations to accept them all).

To contribute I'll ask people that contribute to release copyright to me,
or to give me right to relicense the code as I see fit .
(You can add a "as long as its opensource" if you wish, it'll never change :)

The reason for that is to avoid the headhache that angband had with its
free-but-not-modern licence. This way if a better licence pops up I can
use it easily without having to hunt everybody that contributed and that
might have since then disappeared.