Just so you know, we don't know the file format for every file. If it's just a bunch of random characters, it's probably a .zip or .jar.

function outlineGUI(inv: inventory, size: number, outline: item) :: inventory:
	if {_size} <= 6:
		set slots (all numbers from 0 to 8) of {_inv} to {_outline}
		set {_slots} to {_size} * 9
		if {_slots} > 0:
			set {_check} to 9
			remove 9 from {_slots}
			loop {_slots} times:
				if mod({_check}, 9) is 0:
					set slot {_check} of {_inv} to {_outline}
					set slot ({_check} - 1) of {_inv} to {_outline}
				add 1 to {_check}
			loop 9 times:
				set slot {_slots} of {_inv} to {_outline}
				add 1 to {_slots}
	else:
		set slot 0 of {_inv} to barrier named "&4Your GUI size is too big!" with lore "&c&oThis message is from the outlineGUI function"
	return {_inv}