Wikipedia chess pieces by Colin M. L. Burnett (Cburnett).
Licensed under CC BY-SA 3.0: https://creativecommons.org/licenses/by-sa/3.0/
Original artwork: https://commons.wikimedia.org/wiki/Category:SVG_chess_pieces
PNG assets redistributed from chessboard-element 1.2.0, chesspieces/wikipedia.
Artwork unchanged.