/usr/include/mrpt/nav/ is in libmrpt-dev 1:1.5.5-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/mrpt/nav/include/
/usr/include/mrpt/nav/include/mrpt/
/usr/include/mrpt/nav/include/mrpt/nav/
/usr/include/mrpt/nav/include/mrpt/nav.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/CAbstractHolonomicReactiveMethod.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/CHolonomicFullEval.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/CHolonomicLogFileRecord.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/CHolonomicND.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/CHolonomicVFF.h
/usr/include/mrpt/nav/include/mrpt/nav/holonomic/ClearanceDiagram.h
/usr/include/mrpt/nav/include/mrpt/nav/link_pragmas.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/
/usr/include/mrpt/nav/include/mrpt/nav/planners/PlannerRRT_SE2_TPS.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/PlannerRRT_common.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/PlannerSimple2D.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/TMoveTree.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/impl_renderMoveTree.h
/usr/include/mrpt/nav/include/mrpt/nav/planners/nav_plan_geometry_utils.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CAbstractNavigator.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CAbstractPTGBasedReactive.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CLogFileRecord.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CMultiObjMotionOpt_Scalarization.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CMultiObjectiveMotionOptimizerBase.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CNavigatorManualSequence.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CReactiveNavigationSystem.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CReactiveNavigationSystem3D.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CRobot2NavInterface.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CRobot2NavInterfaceForSimulator.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/CWaypointsNavigator.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/TCandidateMovementPTG.h
/usr/include/mrpt/nav/include/mrpt/nav/reactive/TWaypoint.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_C.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_CC.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_CCS.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_CS.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_CollisionGridBased.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_DiffDrive_alpha.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CPTG_Holo_Blend.h
/usr/include/mrpt/nav/include/mrpt/nav/tpspace/CParameterizedTrajectoryGenerator.h
/usr/include/mrpt/nav/include/mrpt/reactivenav/
/usr/include/mrpt/nav/include/mrpt/reactivenav.h
/usr/include/mrpt/nav/include/mrpt/reactivenav/CReactiveNavigationSystem.h
/usr/include/mrpt/nav/include/mrpt/reactivenav/CReactiveNavigationSystem3D.h
/usr/include/mrpt/nav/include/mrpt/reactivenav/motion_planning_utils.h