See Invisibles Promotion
Allows promotions to grant units the ability to see one or more invisibility types.
Forum thread here
The invisibility types impacted are those defined in Civ4InvisibleInfos.xml and so this mod will not impact the visibility of spies as they use a different mechanism. In an unmodified system this just means that INVISIBLE_SUBMARINE and INVISIBLE_STEALTH units can be configured to be seen.
In the download I have added the ability to see INVISIBLE_SUBMARINE units to the Combat I promotion to see it in action. I don't recommend keeping this unless you want to seriously nerf submarines in your game
SDK Changes marked with SeeInvisiblePromotion
Added XML tags
SeeInvisible - Comma separated list of invisible types the promotion allows to be seen
See Invisible Promotion 2016-10-05
See Invisible Promotion