Here's a chart that nicely illustrates how the 0.618 and 0.786 levels are frequently used as reversal points by the market.
Price is ping-ponging back and forth between these key levels, and we can also see an almost full Volume Profile (parabolic in shape).
The shape of this VP tells us that all the prices within this given range have been discovered, with the middle areas being the places where the most buying and selling has occurred.
This is a sign of a normal and healthy range.
So, we have the Fib levels working in unison with Volume Profile to paint a picture of a ranging market.