/usr/lib/ is in libmrpt-dev 1:1.5.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/libmrpt-graphs.so
/usr/lib/x86_64-linux-gnu/libmrpt-base.so
/usr/lib/x86_64-linux-gnu/pkgconfig/
/usr/lib/x86_64-linux-gnu/libmrpt-opengl.so
/usr/lib/x86_64-linux-gnu/libmrpt-slam.so
/usr/lib/x86_64-linux-gnu/libmrpt-tfest.so
/usr/lib/x86_64-linux-gnu/libmrpt-detectors.so
/usr/lib/x86_64-linux-gnu/
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-base.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-bayes.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-detectors.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-graphs.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-graphslam.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-gui.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-hmtslam.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-hwdrivers.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-kinematics.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-maps.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-nav.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-obs.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-opengl.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-reactivenav.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-scanmatching.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-slam.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-tfest.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-topography.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/mrpt-vision.pc
/usr/lib/x86_64-linux-gnu/libmrpt-graphslam.so
/usr/lib/x86_64-linux-gnu/libmrpt-gui.so
/usr/lib/x86_64-linux-gnu/libmrpt-hmtslam.so
/usr/lib/x86_64-linux-gnu/libmrpt-hwdrivers.so
/usr/lib/x86_64-linux-gnu/libmrpt-kinematics.so
/usr/lib/x86_64-linux-gnu/libmrpt-maps.so
/usr/lib/x86_64-linux-gnu/libmrpt-nav.so
/usr/lib/x86_64-linux-gnu/libmrpt-obs.so
/usr/lib/x86_64-linux-gnu/libmrpt-topography.so
/usr/lib/x86_64-linux-gnu/libmrpt-vision.so