Unofficial Stockfish fork maintained by Henri Poiters, with Windows AVX2 and AVX-512 builds. Not an official Stockfish release or endorsed by the Stockfish team.
The guide explains independent engine Syzygy EGTB access, Syzygy Direct, normal-search fallback, and how the engine options differ from Fritz's own EGTB settings.
The complete engine source, NNUE network, licence and build scripts are supplied as the explicitly named Stockfish19plus_Source_DATE.zip release asset. GitHub's automatic source archives contain this documentation repository, not the full engine source. Read each release's build provenance for compiler details and the distinction between tested RC builds and final compilations.
GPL-3.0-or-later. No measured Elo gain is claimed.