> “Additionally, in case of future violations ChessBase is required to pay a contractual penalty to the FSFE for each breach of Stockfish’s initial request for ChessBase to cease its violations of the GPL-3.0. Under the terms of the settlement, this amount will be determined at Stockfish’s discretion.”

I’m incredibly surprised that anyone would allow an unlimited/open-ended financial risk like that.

If Stockfish is itself a derivative of any other work used under a GPL license, the Stockfish authors most likely lack the authority to re-license Stockfish to ChessBase under these new terms: This right is specifically withheld to the original authors (i.e of the work of which Stockfish is, arguendo, a derivative) under the GPL.