The partial-resto of my 1970 Challenger hardtop progresses and now I start dealing with seat upholstery. Beginning with rear seat back.

Removing the partially rotted cover I found the upholstery looking not too bad - it's not foam but may be wool or like enwrapped in mull and having a jute backside. I'll use it again, as I also will reuse the additional divider (between feathers and upholstery) out of jute with horizontal wires through it.

But now to my question:
The remaining, metal feather-skeleton has on its top another stripe of jute attached (see pic). It has a wire stitched in on both edges (that's where it has cracked).

What's the duty of that stripe out of jute? What will happen, when it's left away?

Is it appropriate to just use textile cord to knot a rough web instead of that stripe?