/usr/lib/ is in libmagics++-dev 3.0.0-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/magics/
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-config-version.cmake
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-config.cmake
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-config.cmake.tpls
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-import.cmake
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-targets-none.cmake
/usr/lib/x86_64-linux-gnu/cmake/magics/magics-targets.cmake
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/magics.pc
/usr/lib/x86_64-linux-gnu/libMagPlus.so
/usr/lib/x86_64-linux-gnu/libMagPlusDouble.so
/usr/lib/x86_64-linux-gnu/libMagPlusSingle.so