This patch is an alternative to D3487.
0 A.D.'s maps feel rather small, partially because units have relatively high vision ranges. In A23 archers had an attack range of 72+4+4+10=90, currently it's 60+10=70. Because this is much lower than it used to be, the minimum vision range soldiers need (to be able to see enemy soldiers) can be lowered, which is what this patch does:
ram : 80 → 60 infantry: 80 → 70 chariot : 96 → 75 cavalry : 92 → 80 camel : 92 → 85 elephant: 100 → 90
The disadvantage is that bolt shooters have an attack range of 90, which means they can hit infantry without those seeing them. However, that's currently the case already.
See also D3776.