The code is open source, what it uses to print signals is cross and . Bar colors change in relation to where price is according to the 50 day MA. The MA ribbon is used for visualizing trend and using it for dynamic . The ribbon is comprised of the 50 day and 100 day MAs.
Main reason to publish this script is because some like to jumble up scripts together slap some moving averages on it to "follow trend" and then label it an algorithm, market it and sell it to people online. No single system will work 100% of the time, do you due diligence in anything you are interested in buying. Plenty of free scripts in the TV library that can do you justice when trading.
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.