/usr/lib/x86_64-linux-gnu/ is in libkdb3-dev 3.1.0-2.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/KDb3/
/usr/lib/x86_64-linux-gnu/cmake/KDb3/KDbConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/KDb3/KDbConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/KDb3/KDbQCHTargets.cmake
/usr/lib/x86_64-linux-gnu/cmake/KDb3/KDbTargets-debian.cmake
/usr/lib/x86_64-linux-gnu/cmake/KDb3/KDbTargets.cmake
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/pkgconfig/KDb3.pc
/usr/lib/x86_64-linux-gnu/qt5/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/qt_KDb3.pri
/usr/lib/x86_64-linux-gnu/libKDb3.so