The pinned piece detection (chessboard.cpp) and move legality check (move_generator.cpp) are taken from Stockfish
The FENs used for the bench in search_handler.cpp are taken from Alexandria
The static exchange evaluation in search.cpp is taken from Ethereal
The evaluation terms were tuned using GediminasMasaitis' texel-tuner using the lichess-big3-resolved dataset
The values used for move ordering in move_ordering.cpp are taken from Alexandria
The PVS implementation in search.cpp is taken from Weiss
The SEE tests are from Starzix
Testing was performed using OpenBench
And most importantly, the development of this engine would not be possible without the brilliant people in the Stockfish Discord