/usr/lib/ is in libmrpt-dev 1:1.0.2-1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/libmrpt-slam.so
/usr/lib/libmrpt-gui.so
/usr/lib/pkgconfig/mrpt-bayes.pc
/usr/lib/libmrpt-hwdrivers.so
/usr/lib/pkgconfig/mrpt-opengl.pc
/usr/lib/libmrpt-maps.so
/usr/lib/libmrpt-scanmatching.so
/usr/lib/libmrpt-base.so
/usr/lib/libmrpt-kinematics.so
/usr/lib/pkgconfig/mrpt-hwdrivers.pc
/usr/lib/pkgconfig/mrpt-graphs.pc
/usr/lib/pkgconfig/
/usr/lib/pkgconfig/mrpt-srba.pc
/usr/lib/pkgconfig/mrpt-maps.pc
/usr/lib/pkgconfig/mrpt-hmtslam.pc
/usr/lib/pkgconfig/mrpt-kinematics.pc
/usr/lib/pkgconfig/mrpt-base.pc
/usr/lib/pkgconfig/mrpt-gui.pc
/usr/lib/pkgconfig/mrpt-detectors.pc
/usr/lib/pkgconfig/mrpt-scanmatching.pc
/usr/lib/pkgconfig/mrpt-obs.pc
/usr/lib/pkgconfig/mrpt-slam.pc
/usr/lib/pkgconfig/mrpt-vision.pc
/usr/lib/pkgconfig/mrpt-reactivenav.pc
/usr/lib/pkgconfig/mrpt-topography.pc
/usr/lib/pkgconfig/mrpt-graphslam.pc
/usr/lib/libmrpt-detectors.so
/usr/lib/libmrpt-topography.so
/usr/lib/libmrpt-opengl.so
/usr/lib/libmrpt-vision.so
/usr/lib/libmrpt-hmtslam.so
/usr/lib/libmrpt-reactivenav.so
/usr/lib/libmrpt-obs.so