It's a very old line from the stone age. I think in the States is called dacron spun braid. So certainly it's not slippery.

But you brought me on an idea. I still have an old mainsheet with no core in it. I bought it a few years ago in the Catsailors store overhere (new england rope???). Forgot the name.

After one trial, I didn't use it anymore, because it had the tendency to get stuck between the cams of the cleat.
Because there is no core, which is "the meat" for the cams.

So, it happened that I could not loose my mainsheet on time when it was needed in a windblow.

But in this case with my jibsheet which loosens when I don't want it, it maybe the solution.

Have to try it.