The "Signal Viewer" script is a debugging tool that can be used for the signal of a Signal Indicator script like the "Two MA Signal Indicator" or the "Template Signal Indicator". This script will visualize the signal based on the convention that was defined in the settings. Also, alerts will be produced based on this convention. It's useful to be used before you connect the signal indicator script to a template strategy like the "Template Trailing Strategy" script. You can cross-validate the correctness of the signal that the indicators emit and make sure it is aligned with the expected behavior after the decomposition of the signal using the convention described in the settings. Please make sure that the connection in the "Signal Viewer" script matches the convention used by the template strategy script.
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.