/usr/include/octomap/ is in liboctomap-dev 1.6.8+dfsg-1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/octomap/AbstractOcTree.h
/usr/include/octomap/AbstractOccupancyOcTree.h
/usr/include/octomap/ColorOcTree.h
/usr/include/octomap/CountingOcTree.h
/usr/include/octomap/MCTables.h
/usr/include/octomap/MapCollection.h
/usr/include/octomap/MapCollection.hxx
/usr/include/octomap/MapNode.h
/usr/include/octomap/MapNode.hxx
/usr/include/octomap/OcTree.h
/usr/include/octomap/OcTreeBase.h
/usr/include/octomap/OcTreeBaseImpl.h
/usr/include/octomap/OcTreeBaseImpl.hxx
/usr/include/octomap/OcTreeBaseSE.h
/usr/include/octomap/OcTreeBaseSE.hxx
/usr/include/octomap/OcTreeDataNode.h
/usr/include/octomap/OcTreeDataNode.hxx
/usr/include/octomap/OcTreeIterator.hxx
/usr/include/octomap/OcTreeKey.h
/usr/include/octomap/OcTreeLUT.h
/usr/include/octomap/OcTreeLUTdefs.h
/usr/include/octomap/OcTreeNode.h
/usr/include/octomap/OcTreeStamped.h
/usr/include/octomap/OccupancyOcTreeBase.h
/usr/include/octomap/OccupancyOcTreeBase.hxx
/usr/include/octomap/Pointcloud.h
/usr/include/octomap/ScanGraph.h
/usr/include/octomap/math/
/usr/include/octomap/math/Pose6D.h
/usr/include/octomap/math/Quaternion.h
/usr/include/octomap/math/Utils.h
/usr/include/octomap/math/Vector3.h
/usr/include/octomap/octomap.h
/usr/include/octomap/octomap_deprecated.h
/usr/include/octomap/octomap_timing.h
/usr/include/octomap/octomap_types.h
/usr/include/octomap/octomap_utils.h