Stockfish chess engine — source and license information
=======================================================

The engine files in this directory are the Stockfish chess engine compiled to
WebAssembly/JavaScript. Stockfish is free software released under the GNU
General Public License version 3 (GPL-3.0). The full license text is in
LICENSE.txt in this directory.

Chess It Up serves these files to your browser, so under GPL-3.0 section 6 you
are entitled to the corresponding source code. Links to the exact upstream
sources are below.


1. stockfish-18-lite-single.js / stockfish-18-lite-single.wasm  (primary engine)
--------------------------------------------------------------------------------
  Stockfish.js 18, (c) 2026 Chess.com, LLC
  WASM build source:  https://github.com/nmrugg/stockfish.js
  Engine source:      https://github.com/official-stockfish/Stockfish
                      (c) T. Romstad, M. Costalba, J. Kiiski, G. Linscott
                      and other contributors
  NNUE network:       nn-9067e33176e8.nnue, by Linmiao Xu (linrock)
                      https://tests.stockfishchess.org/nns?network_name=nn-9067e33176e
  License:            GPL-3.0

  This is the "lite single-threaded" build. It is unmodified; Chess It Up
  communicates with it over the standard UCI protocol and has made no changes
  to the engine itself.


2. stockfish.js  (legacy fallback engine)
------------------------------------------
  Stockfish, (c) T. Romstad, M. Costalba, J. Kiiski, G. Linscott
  and other contributors
  Multi-variant fork:  https://github.com/ddugovic/Stockfish
                       (Daniel Dugovic and contributors)
  WASM/JS build:       https://github.com/niklasf/stockfish.js
                       compiled by Niklas Fiekas using Emscripten and Binaryen
  License:            GPL-3.0

  Used only as a fallback when the primary build cannot be loaded. This file
  does not record its upstream Stockfish version number in its header.
  Unmodified.


Note on Chess It Up itself
--------------------------
Chess It Up is a separate program that communicates with Stockfish by passing
UCI text messages to it in a Web Worker. Stockfish is not linked into or
combined with the Chess It Up application code.

Questions: thesaadster.dev@gmail.com