Hi LEIT,
That’s just a variable of type Actor set as an array. We’re using it to make a list of Actors hit by Line Trace and hiding them all, then unhiding them when Line Trace is done.
This isn’t a perfect setup, though; in effect, this will hide all Actors character runs behind and they will all remain hidden until character isn’t behind anything. That’s probably not what you want, and you’d need to implement a way of unhiding an Actor once Line Trace isn’t hitting it in particular. That’s a bit more complex, but this is this setup is a good way to start.