Here's an example of script taken out of unit_upg.cfg:


[*] : struct.begin
UpgradeID = 51
Hint = Recuperation +1
OnlyOnce = 0
Upgrades : struct.begin
[*] : struct.begin
AbilityID = 21
Quantity = 1
struct.end
struct.end
struct.end

Some upgrades have =1 as entry for OnlyOnce, I've been testing both states in order to find out what their ingame meaning is but it doesn't seem to have any effect.

Does anyone know what exactly this tagline should cause?

This is a unit upgrade. "onlyOnce=0" means you can get it more than once. If you set it to "1", it would be a one time only upgrade.

That's what I initially thought as well. But line 1307
[*] : struct.begin
UpgradeID = 104
Hint = Затаптывание+2
OnlyOnce = 1
Upgrades : struct.begin
[*] : struct.begin
AbilityID = 63
Quantity = 2
struct.end
struct.end
struct.end

raised some doubts. This is a +2 upgrade to a War Elephants base Trample15 ability. Which it can get 4 or 5 times.

I then made a test and labelled the common "Hitpoints+1" as OnlyOnce = 1, and introduced that upgrade to every level to a testchar, and was able to get it multiple times.

I then thought this line was used to prevent that you're offered the exact same upgrade twofold for a single level - but the game doesn't do this anyway under no circumstances. (it rather bugs out...)

I do vaguely remember someone writting that specific upgrades do get a special consideration independant of the chance/possibility set in unit.cfg, but this is just a guess and I have no clue how I could confirm that or find out how much the influence in actual numbers is.....