/usr/include/geos/geomgraph/index/ is in libgeos-dev 3.2.2-3ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/geos/geomgraph/index/EdgeSetIntersector.h
/usr/include/geos/geomgraph/index/MonotoneChain.h
/usr/include/geos/geomgraph/index/MonotoneChainEdge.h
/usr/include/geos/geomgraph/index/MonotoneChainIndexer.h
/usr/include/geos/geomgraph/index/SegmentIntersector.h
/usr/include/geos/geomgraph/index/SimpleEdgeSetIntersector.h
/usr/include/geos/geomgraph/index/SimpleMCSweepLineIntersector.h
/usr/include/geos/geomgraph/index/SimpleSweepLineIntersector.h
/usr/include/geos/geomgraph/index/SweepLineEvent.h
/usr/include/geos/geomgraph/index/SweepLineEventObj.h
/usr/include/geos/geomgraph/index/SweepLineSegment.h