Credits and sources

The play page runs three engines side by side. Each one keeps its own license, and the source for what is served here is public.

Experion

MIT license. Source: github.com/joeyrobert/experion. The WebAssembly build is produced from src/experion_wasm.cr by tools/build_wasm.sh.

Fruit 2.1

© 2004–2005 Fabien Letouzey. GNU General Public License, version 2 or (at your option) any later version. The unmodified source, apart from one documented change so that it can wait for input under WebAssembly, is in third_party/fruit-2.1 and is compiled by tools/build_fruit_wasm.sh. The binary served here is built from exactly that source.

CeruleanJS

© Joey Robert. GNU General Public License, version 3. Source: bitbucket.org/joeyrobert/ceruleanjs. The worker served here is the npm run build-web output of that repository; see site/engines/ceruleanjs for the license text and the exact commit. Its opening book is the gm2001 Polyglot book from ceruleanjs_opening_books (games by players rated 2530 and above, compiled by Oliver Deville).

Crafty

Crafty is not bundled. Its license does not allow redistribution without the authors' permission, so it is only available through the optional local bridge, which drives a copy you already have on your own computer.

Other

Move legality and game-end rules come from chess.js (BSD 2-clause, Jeff Hlywa). The Experion network was trained on games from the CCRL 40/15 rating list.