With inputs for the moving average, Bullish overshoot percentage, and bearish overshoot percentage, this indicator is attempting to show market tops based on the difference between the current price of an asset and how far away it is from its moving average.
If you have the bullish overshoot percentage set to 1.5:
let's say price is currently at 20,000 and the moving average is around 6500.
The script calculates 20,000/6500 = 3.07
Then, there is a boolean comparison asking if 3.07 > 1.5.
Since it is, the script will create a "SHORT" flag above that candlestick.