The indicator shows John Ehlers trendline on the price chart.
Calculations:
Instantaneous Trendline = MVA(Price, Period) + SmoothSlope/2,
where:
SmoothSlope[i] = (Slope[i] + 2*Slope[i-1] + 2*Slope[i-2] + Slope[i-3])/6, Slope[i] = Price[i] - Price[i-Period+1]