/usr/lib/x86_64-linux-gnu/ is in libkf5akonadisocialutils-dev 4:15.12.3-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/cmake/
/usr/lib/x86_64-linux-gnu/cmake/KF5AkonadiSocialUtils/
/usr/lib/x86_64-linux-gnu/cmake/KF5AkonadiSocialUtils/KF5AkonadiSocialUtilsTargets-debian.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5AkonadiSocialUtils/KF5AkonadiSocialUtilsConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5AkonadiSocialUtils/KF5AkonadiSocialUtilsConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5AkonadiSocialUtils/KF5AkonadiSocialUtilsTargets.cmake
/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_AkonadiSocialUtils.pri
/usr/lib/x86_64-linux-gnu/libKF5AkonadiSocialUtils.so