About & Licenses
Elo Ladder
Elo Ladder is free software
Elo Ladder is licensed under the GNU General Public License, version 3 (GPLv3). You can read, copy, change and share it under the terms of that license. The complete source code is at github.com/kaceiam/elo-ladder.
Read the full license: GNU General Public License v3 (also at gnu.org/licenses/gpl-3.0.html).
This program comes with ABSOLUTELY NO WARRANTY, to the extent permitted by law.
Stockfish
The chess engine behind the bots is Stockfish (stockfishchess.org), Copyright © The Stockfish developers, built for the web by the stockfish.js project. Stockfish is free software licensed under the GNU GPL v3. Its source code is available at github.com/official-stockfish/Stockfish and github.com/nmrugg/stockfish.js. The exact engine files used in this app are in the app's source code (vendor/stockfish).
chess.js
Copyright (c) 2020, Jeff Hlywa (jhlywa@gmail.com) All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
PeerJS
Copyright (c) 2015 Michelle Bu and Eric Zhang, http://peerjs.com Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
QR Code Generator
Copyright (c) 2009 Kazuhiko Arase URL: http://www.d-project.com/ Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php The word "QR Code" is registered trademark of DENSO WAVE INCORPORATED.
Training puzzles
Some training exercises come from the Lichess puzzle database, released into the public domain (CC0).