The goal of the Einstein Toolkit Consortium is to develop software in support of relativistic astrophysics research and education. A core goal of the consortium is to provide the widest availability and impact of the Einstein Toolkit. Therefore all software is developed and distributed under an open source license.
Developers for the Einstein Toolkit are free to choose an appropriate open source license. Since this list is quite long and some of the licenses are incompatible, the Einstein Toolkit team suggests that developers choose a license which is compatible to the GPL license.
Some software will be preexisting and not necessarily free from existing third-party copyrights and licenses. In the event that the Einstein Toolkit Consortium wishes to use or to modify, improve, and/or distribute such software, it will, with its collaborators, determine who the copyright holders are and enter into an agreement to have the resulting software released under an open source license. In exceptional cases, the Consortium will consider a different license as long as it is free for non-commercial use but otherwise satisfies the principles of open source software.