The scarletbook-rs C library linked into pysacd's engine contains, besides
scarletbook-rs itself (scarletbook-rs-LICENSE-MIT), the Rust standard library
and these crates. Each is dual-licensed "MIT OR Apache-2.0"; pysacd uses them
under the MIT licence, which is compatible with pysacd's GPL-2.0-or-later.

  Rust standard library (core, alloc, std)
                             Copyright (c) The Rust Project Contributors
  rayon 1.12.0, rayon-core 1.13.0
                             Copyright (c) 2010 The Rust Project Developers
  crossbeam-deque 0.8.8, crossbeam-epoch 0.9.21, crossbeam-utils 0.8.23
                             Copyright (c) 2019 The Crossbeam Project Developers
  either 1.19.0              Copyright (c) 2015
  thiserror 2.0.21           (David Tolnay; the MIT text, no copyright line)

The standard library's compiler_builtins also carries code from LLVM's compiler-rt,
under Apache-2.0 WITH LLVM-exception; the exception waives the attribution terms for
compiled object code such as this.

The MIT licence, as each of them states it:

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.
