SoIndexedMarkerSet(3) on Linux
The text 380eb78fa3b9, as Debian 8 (Jessie) shipped it.
The SoIndexedMarkerSet class is used to display a set of bitmap markers at 3D positions. This node either uses the coordinates currently on the state (typically set up by a leading SoCoordinate3 node in the scenegraph) or from a SoVertexProperty node attached to this node to render a set of 3D points.