/usr/lib/ is in libkf5followupreminder-dev 4:17.12.3-0ubuntu1.
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/KF5FollowupReminder/
/usr/lib/x86_64-linux-gnu/cmake/KF5FollowupReminder/KF5FollowupReminderConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5FollowupReminder/KF5FollowupReminderConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5FollowupReminder/KF5FollowupReminderTargets-debian.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5FollowupReminder/KF5FollowupReminderTargets.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_FollowupReminder.pri
/usr/lib/x86_64-linux-gnu/libKF5FollowupReminder.so