License for vendored XKCP (eXtended Keccak Code Package) components
under src/third_party/shake_xkcp/.

The Keccak sponge function was designed by Guido Bertoni, Joan Daemen,
Michael Peeters and Gilles Van Assche. The vendored implementation files
carry the following notice from their authors ("the implementer",
as denoted in each file header — Gilles Van Assche, Ronny Van Keer,
and/or the designers):

    To the extent possible under law, the implementer has waived all
    copyright and related or neighboring rights to the source code in
    the corresponding file.
    https://creativecommons.org/publicdomain/zero/1.0/

That is, these files are distributed under the CC0 1.0 Universal
public-domain dedication as declared in their headers. See each file's
header for its exact attribution. Files in this directory that were
added or modified by the SNOVA Team are covered by the top-level MIT
LICENSE of this distribution.
