This deprecates the project.license table in favor of a standardized SPDX license string, as well as the temporary setuptools-specific tools.setuptools.license-files table in favor of project.license-files.

tools.setuptools.license-files and project.license-files can't be set at the same time. Considering that setuptools 77 was only released in March, we should wait a bit more before switching the metadata format, as recent enough setuptools versions might not be packaged yet on all Linux distros where we have recent Streamlink releases packaged.

$ pip install .
...
$ grep -E '^License' $VIRTUAL_ENV/lib/python3.13/site-packages/streamlink-7.2.0+13.g1cebf437.dist-info/METADATA
License-Expression: BSD-2-Clause
License-File: LICENSE
$ cat $VIRTUAL_ENV/lib/python3.13/site-packages/streamlink-7.2.0+13.g1cebf437.dist-info/licenses/LICENSE
Copyright (c) 2011-2016, Christopher Rosell
Copyright (c) 2016-2025, Streamlink Team
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.