Currently different support units have different vision range values, but all of them are much lower that of soldiers, which is perceived as sexist by some on the forums (see comments in https://wildfiregames.com/forum/topic/37850-revealing-attackers-in-fog-of-war/ ).
This patch gives all support units the same vision range as infantry.
As a consequence, espionage is more effective too (see also D3565).