This seems to be how triggers work...
itemMod -> Status effect ApplyOnEvent: kill or whatever -> a Status Effect that does nothing we'll call it "null_effect"
also in ItemMod -> Ability containing a Function Called condition: If (character) has null effect -> Apply the effects in an ATTACK
As you can see, one branch of the object chain seems to apply a flag (null_effect) and the other branch uses an ability to do the function call to check whether the flag is up or not, and apply the attack if it is.
For functions, the Parameter GUIDs are here: https://eternity.obsidian.net/game-data-formats/instanceids
The FunctionHash is the same, so just find an existing Parameter and copy the FunctionHash Number from underneath it (the green one, if you're using VSCode).
Parameter Hashes correspond to parameter GUIDs, so to find the ParameterHash for an attack/race/statuseffect etc, you need;
search for the name of the Attack in the Attacks file or name of the race in ..er.. characters or global?, name of the Status Effect in Status Effects file etc. then copying it's GUID.
then search the StatusEffects file for the GUID being used in another condition, then copy it's corresponding ParameterHash.
*I don't know modern programming terminology, so if I've got the terms wrong, please forgive/correct me.