None of the traders I know use indicators. Many of them run custom scripts, but they don't use any indicators. I also don't.
Based on searching online, xmaster is an indicator to generate buy or sell signals. I have not seen their documentation to know how they generate the signal, but I'll not trust it.
It is a general EA scam.
I am on side of the argument, if you have an indicator or a system that has an edge in the market, why will you give it away (for free or for a price), when you can make money from trading it.