Balderstrom
Emperor
"- Collateral damage modifiers, collateral damage immunity, and air defense modifiers, multiply instead of add."
What does this mean in practice?
It means, things that add +XX% to collateral defense, or +XX% to damage
Will actually increase the base by XX%
Previously in the code, it would start with a base (integer) of 100 and then the code would add or subtract integers from/to 100. There were a number of cases where you could actually wind up with a value less than 0.
And when you would add +xx% attack -xx% defense the code would just add and subtract integer values, instead of actually applying a percentage increase/decrease of the related values (ie multiplication).
I mentioned this over in Solver's thread when I used to participate in the Collateral debate. But I believe I was overruled

For Example:
A unit with +100% Collateral damage, 100 + 100% = 200
vs a unit with +50% Collateral Protection: 200 - 50 = 150
So you take 150% damage from Collateral damage, instead of 100%,
Another Example:
A unit with +100% Collateral damage, 100 + 100% = 200
vs a unit with +100% Collateral Protection: 200 - 100 = 100
So you take 100% damage, instead of 0.
A unit with 50% Collateral protection should take 1/2 damage.
A unit with 100% protection should be immune

So if the code is now doing multiplication instead of addition, it should actually work as the in-game descriptions state it works.