Example: Asian session
If session time is 1700 - 0200, the indicator will find the high and low of that session then plot its fib extension lines and background outside of hours provided.
Currently supports 4 keys levels that can be changed under settings.
If you don't want the lines to display and only the background colors, you can uncheck the lines under the indicator settings -> styles.
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.