Border Edge Highlighting

Could we please have border edge highlighting in edit mode?
It makes modeling so much better. Blender: I have a working prototype, it should be trivial for a blender C dev to implement this:
Please add this feature!
We can just have a new option next to: Creases | Sharp | Bevel | Seams

    bpy.ops.mesh.select_all(action='SELECT')
    bpy.ops.mesh.mark_seam(clear=True)
    bpy.ops.mesh.select_all(action='DESELECT')
    bpy.ops.mesh.select_non_manifold()
    bpy.ops.mesh.mark_seam(clear=False)
    bpy.ops.mesh.select_all(action='DESELECT')