It is a feature to 'recognise' certain engine modes. Atleast thats how they mean it, it is up to you what you do with it. When you push your throttle forward to before the resistance, it is supposed to represent full throttle, and when you push it after the resistance so to say, you go afterburner. When you put it back, before the resistance is supposed to mean minimum throttle and after the resistance would mean Idle/Reverse thrust. However, it is up to you how you use and configure this.
I hope this made things clear, if not let me know, and I will try to make a image.