This patch changes the vision of walls and similar structures:range of wall segments, palisades, Iberian monument, Mauryan pillar, and Roman arch to 1. This means you can select them, but they won't reveal their surrounding area. They're basically pieces of stone, wood, and metal, so it's unnatural to have them see things. (For comparison, field has 0.) Ranged infantry on walls still has an extensive range, of course.
* Wall segments, palisades, Iberian monument, Mauryan pillar, Roman arch get a vision range of 1. This means you can select them, but they won't reveal their surrounding area. They're basically pieces of stone, wood, and metal, so it's unnatural to have them see things. (For comparison, field has 0.) Ranged infantry on walls still has an extensive range, of course.
* Gates keep a vision range of 20, the same as their pass range (the distance at which units are detected and trigger the gate to open or close).
* Wall towers are garrisonable and have a ranged attack, which means they need to have a vision range larger than their maximum attack range, hence changed from 60 to 7580.