Guides/Info about signals:
The variable is just sent.
when you see a signal described in the documents like this:
area_enter ( Object area ) . The things between the
( ) are automatically sent.
All you have to do is connect your signal with
connect() and then give room for the variables in the function that is being called.
You can also add variables to a signal.
with extra vars:
connect("area_enter", self, "_on_object_enters_area", [myVar1, myVar2])
connect("area_enter", self, "_on_object_enters_area")
but you need to make room for them in your function that gets triggered:
func signalTriggerThis(area, myVar1, myVar2):