My reasoning behind this very simple script is that the low liquidity and participation of the overnight session creates a tendency for moves at extremes to mean revert. Let me know what you think.
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.