/usr/lib/ is in libkf5mailimporter-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/KF5MailImporter/
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporter/KF5MailImporterConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporter/KF5MailImporterConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporter/KF5MailImporterTargets-debian.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporter/KF5MailImporterTargets.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporterAkonadi/
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporterAkonadi/KF5MailImporterAkonadiConfig.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporterAkonadi/KF5MailImporterAkonadiConfigVersion.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporterAkonadi/KF5MailImporterAkonadiTargets-debian.cmake
/usr/lib/x86_64-linux-gnu/cmake/KF5MailImporterAkonadi/KF5MailImporterAkonadiTargets.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_MailImporter.pri
/usr/lib/x86_64-linux-gnu/qt5/mkspecs/modules/qt_MailImporterAkonadi.pri
/usr/lib/x86_64-linux-gnu/libKF5MailImporter.so
/usr/lib/x86_64-linux-gnu/libKF5MailImporterAkonadi.so