Where the light is reflecting off of the back of them in photo #1, it makes them look either braided, or shielded. Then in the second photo, it looks like a wire in spiral wrapped around them, at least to me.
I have a headphone extension cable I bought years ago, that has a bad connection in the jack end. When these are used, it sounds just like their plugged in the headphone preamp itself. No added coloration, or loss of anything. I have a generic extension cable that I bought years back that I can't remember where it was from. Both have no markings. The unused spare one sounds so bad, I can't even use it. I think I could buy some discount store one that may sound better, but that's not saying much. I guess I'll just see if I could find a halfway decent jack to fix the old one. I just brought this up because I'd like to find close to, or exact replacement of the original, to have for a spare.