linux/LICENSES/preferred/LGPL-2.1

Valid-License-Identifier: LGPL-2.1
Valid-License-Identifier: LGPL-2.1-only
Valid-License-Identifier: LGPL-2.1+
Valid-License-Identifier: LGPL-2.1-or-later
SPDX-URL: https://spdx.org/licenses/LGPL-2.1.html
Usage-Guide:
  To use this license in source code, put one of the following SPDX
  tag/value pairs into a comment according to the placement
  guidelines in the licensing rules documentation.
  For 'GNU Lesser General Public License (LGPL) version 2.1 only' use:
    SPDX-License-Identifier: LGPL-2.1
  For 'GNU Lesser General Public License (LGPL) version 2.1 or any later
  version' use:
    SPDX-License-Identifier: LGPL-2.1+
License-Text:

GNU LESSER GENERAL PUBLIC LICENSE
Version 2.1, February 1999

Copyright (C) 1991, 1999 Free Software Foundation, Inc.
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.

[This is the first released version of the Lesser GPL. It also counts as
the successor of the GNU Library Public License, version 2, hence the
version number 2.1.]

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signature of Ty Coon, 1 April 1990
Ty Coon, President of Vice
That's all there is to it!