In addition to the opening hours of session, the pre-market and closing time periods are also marked with a grey color
Generally these are consided period of high activity and can experience more volatility in these periods
I also have enabled it to display the session times even on weekends. There is no session open at such times but heightened activity is noticed in these periods even on weekends.
If want to disable showing it on weekends, then remove ":1234567" from all the lines in code
-Added day of week info
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.