Hi, I recently bought a H14 turbo with a similar line with it. I worked out that it was to help step the mast single-handed and actually replaced the standard front rigging. Mine has a long rope with a block pulley attached and if you pin the mast with the mast stepping set-up, in therory you should be able to raise the mast yourself, while standing at the front of the boat. I tried it on a still day and it did not go too well as you have no control over the mast from swinging from side to side! I don't step the mast that way now!!

The rope is attached to the top of the jib via a pulley.

Well, thats what my one has got... a consideration for you as to what it maybe anyway.