Auto Trendlines display a series of trendlines on the chart, these can highlight points of support or resistance depending on the current price trend.
A higher SR significance allows the user to obtain longer-term trendlines. The two trendlines prior to the most recent one are extended and can be used as support/resistances.
A trendline is more significant when it was previously tested.
Note that these trendlines do not appear in real-time and that the most recent trendline can continuously readjust.