Information from the author:
Brainfish is a standard Stockfish chess engine extended by a general book format that is capable of handling a reduced part of Cerebellum, which is an innovative chess opening and playing book. In Brainfish, the book moves are only used in engine games, not in analysis mode.
All moves in the published book Cerebellum_light.bin generated by Cerebellum were calculated by using
Stockfish as analysis engine, without using statistics. Then those moves where recalulated by the Cerebellum Library using a graph algorithm that makes all scores in the library consistant. Consistant scores means for example, in case the starting position has a score of 0.2 and a best move is 1.e4, the position after 1.e4 must have the score -0.2. Additionally, some others properties are found, like the best main line of a position and possible Transitions.
Hence, when Brainfish is playing moves that are in the Cerebellum book, it plays like Stockfish regarding the evaluation, only at a much higher skill level. Pondering is only active after the last move out of the book has been played.
The lines in Cerebellum_light.bin are in some cases reaching the late middlegame and endgame.
BrainFish is licensed unter the GPL, which includes the access code to the general book format.