Hello,
This indicator is called MA_Color in MT4. It's basically 2 EMAs calculated into one line. When they crossover, that line changes colors. Also, if the candle body happens to hit the MA line, the line will change color as well to yellow ( in this case ) to indicate indecision. Only the body of the candle though, it won't will go back to the color it was before if the body moves away from the line again.
I've attached a picture so you can get the idea a little better.
the EMAs are as follow:
5 EMA, set to close, green color
14 EMA, set o close, red color
thanks for any help!