The indicator draws levels based on the overbought and oversold values of the RSI indicator.
The maximum values are taken into account, which are equal to or exceeded certain limits.
That is, for example, when the price has gone into the overbought zone, the highest price is selected from all prices in this zone for this period of time, and as soon as the indicator value returns to a value below the overbought value, the level is fixed and the calculation of new values begins.
The same is for oversold values.
There is a setting to display the same levels on the chart when the price left the overbought or oversold zone and for the first time crossed the 50% border of the RSI indicator.
In case of repeated passes of the central line, the calculations of the passing of the middle line are not performed, the indicator switches to the calculations of overbought or oversold conditions.
To display levels from 50% of the RSI value, there is a setting at what price to draw the line: either at high / low prices, or at close.
Configurable RSI period, RSI levels and line color.
The first screenshot shows only overbought and oversold levels.
On the second - the same thing + the first crossing of 50% RSI.
RSI indicator at the bottom of the chart for clarity.