The ability to change how visible the hud is compared to the game in the background on a scale of 0-100%. Useful if you want to keep the hud up but not have it be so obvious and for those who are visually impaired. 100% could be the hud having a fully black background and/or border, close to 0 would have it faint, just enough to see. I believe there is something like this in tsc already.
Sometimes the instructions in the top left do accidentally come up at a lower opacity so the game can certainly accommodate it. DTG do seem to have a player settings phobia for TSW.
