debian/copyright: update to reflect last commit, also following:

testcommon:  mark as BSD-3-clause from LGPL-2.1+ as permission
  given (I think) by mailing list:
  https://sourceforge.net/p/zint/mailman/message/30810495/

backend/tests/testcommon.c

@@ -30,9 +30,11 @@
 /*
  * Adapted from qrencode/tests/common.c
  * Copyright (C) 2006-2017 Kentaro Fukuchi <kentaro@fukuchi.org>
+ * originally licensed under LGPL-2.1+ but permission given to change to
+ * BSD-3-clause:
+ * https://sourceforge.net/p/zint/mailman/message/30810495/
  */
-/* Due to above: */
+/* SPDX-License-Identifier: BSD-3-Clause */
-/* SPDX-License-Identifier: LGPL-2.0-or-later */
 
 #ifdef _WIN32
 #include <windows.h>

backend/tests/testcommon.h

@@ -30,9 +30,11 @@
 /*
  * Adapted from qrencode/tests/common.h
  * Copyright (C) 2006-2017 Kentaro Fukuchi <kentaro@fukuchi.org>
+ * originally licensed under LGPL-2.1+ but permission given to change to
+ * BSD-3-clause:
+ * https://sourceforge.net/p/zint/mailman/message/30810495/
  */
-/* Due to above: */
+/* SPDX-License-Identifier: BSD-3-Clause */
-/* SPDX-License-Identifier: LGPL-2.1+ */
 
 #ifndef Z_TESTCOMMON_H
 #define Z_TESTCOMMON_H

debian/copyright

@@ -15,12 +15,11 @@ Files: backend/*
 Copyright:
     Copyright (C) 2007-2026 Robin Stuart <rstuart114@gmail.com>
     Copyright (C) 2014-2026 Harald Oehlmann <oehhar@users.sourceforge.net>
-    Copyright (C) Cliff Hones 2004
     Copyright (c) 2004 Adrian Kennard, Andrews & Arnold Ltd
+    Copyright (c) 2004 Andrews & Arnold Ltd
     Copyright (c) 2015, Harald Kuhr
     Copyright (C) 1988 Bob Montgomery
     Copyright (C) 2024-2025 Antoine Merino <antoine.merino.dev@gmail.com>
-    Copyright (c) 2006 Stefan Schmidt <stefan@datenfreihafen.org>
     Copyright (C) 2016 Zoe Stuart
     Copyright (C) 2006-2009 United States Postal Service
 License: BSD-3-Clause
@@ -124,16 +123,6 @@ Copyright:
     Copyright (C) 1987-2003 Free Software Foundation, Inc.
 License: GPL-2.0-or-later
 
-Files:
-    backend/tests/testcommon.*
-    backend/tests/CMakeLists.txt
-    cmake/zint_add_test.cmake
-    frontend/tests/CMakeLists.txt
-Copyright:
-    Copyright (C) 2019-2026 Robin Stuart <rstuart114@gmail.com>
-    Copyright (C) 2006-2017 Kentaro Fukuchi <kentaro@fukuchi.org>
-License: BSD-3-Clause and LGPL-2.0-or-later
-
 Files:
     backend/tests/fuzz/Dockerfile
     backend/tests/fuzz/build.sh
@@ -465,20 +454,6 @@ License: ISC
  OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  PERFORMANCE OF THIS SOFTWARE.
 
-License: LGPL-2.0-or-later
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU Library General Public License as published
- by the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
- ․
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- GNU Library General Public License for more details.
- ․
- On Debian systems, the complete text of the GNU Library General Public
- License Version 2 can be found in "/usr/share/common-licenses/LGPL-2".
-
 License: LGPL-2.1-or-later
  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU Library General Public License as published