Stockfish: Chess GPLv3 Violation Lawsuit Settles

SFC Named as Trusted Party To Verify Future Corresponding Source

November 28, 2022

Stockfish, a Free and Open Source Software (FOSS) chess engine, has announced the settlement of their lawsuit against ChessBase GmbH regarding violations of Stockfish's license, the General Public License, version 3 (GPLv3). Software Freedom Conservancy is excited to announce our role in this historic violation settlement. Specifically, SFC has been named in the settlement agreement as the trusted third-party to analyze and approve any complete “Corresponding Source” releases by ChessBase in the future.

SFC is honored that the parties chose us to carry out this critical duty. As a litigant ourselves in unrelated copyleft enforcement litigation, we know well that ongoing compliance, and assuring that the rights of the community of users remains respected for the years after the litigation completes, is the most important work of software freedom. We also appreciate the trust that the FOSS community places in SFC as arbiters on behalf of consumers and users, of what various copyleft licenses (such as the GPLv2 and GPLv3) require with regard to complete, corresponding source (CCS).

Too often, those who enforce the GPL focus so much on the copyright infringement they have suffered and forget the policy goal of all copyleft licenses: to guarantee that users and consumers get the methods, means, and technical details on how to make real use of the software rights and freedoms that the licenses promise. We congratulate both parties in this litigation for coming to an amicable agreement that makes a plan to put those rights of users first and foremost in an ongoing way.