This indicator plots fibonacci channel on last swing high low that can be changed from input variable "ExtDepth"

55 is a best parameter which is set by default. It plots a fibonacci channel with internal levels of 0.236, 0.382, 0.5, 0.618 and 0.786

You can also change NUMB from input, which will change the trendline to previous swing high low

These Internal levels are often used by price action traders