Standard deviation band is + stdev and - stdev.
Fibonacci levels are + stdev * fib ratio and - stdev * fib ratio (0.382 / 0.5 / 0.618 / 1.618 / 2.618).
Used like a moving average, but also shows probable price range based on past , and helps to recognize levels, trends and trend momentum based on the Fibonacci levels.
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.