GAMGI is not in the Public Domain, so normal copyright laws apply.
According to current EU and US laws of intellectual rights, GAMGI
code and documentation will be automatically Public Domain property
only 70 years after the death of the authors.
As granted by the current laws of copyright and intellectual rights,
all contributors (or their employees, in some cases) to the GAMGI project
remain the sole owners of their intellectual property and keep full
rights to the code and documentation given to the GAMGI project,
so in particular they are free to use them in closed-source software
projects, books of their own, etc.
What they cannot do is to take away what they have already given,
to the GAMGI project and the free software community at large.
A time clause explicitly forbidding this is present in every software
or documentation free license.
Copyright ownership was registered in 2001 for GAMGI 0.07.17
and in 2004 for GAMGI 0.09.28, by GAMGI first author, Carlos Pereira.
Other contributors to GAMGI source code remain the sole owners
of their copyrights and are responsible for registering and
defending them.