There are several modules that can be attached to 2D Terrain as a components.
Every module has it's Parent Terrain 2D assigned.
Cap
Adds new GameObject with it's own Mesh Renderer component. Generates configurable mesh along the Path Points of Parent.
Edge Collider
Generates Edge Collider 2D along the Path Points of Parent.
Polygon Collider
Wraps the whole Parent with Polygon Collider 2D.
3D Mesh Collider
Generates 3D Mesh Collider along the Path Points of Parent.
Path Snap Group
Aligns all child transforms to Parent path by Y-axis.