The Fibonacci Moving Average (FMA) is a technical analysis tool that uses a weighting system based on the Fibonacci sequence to smooth out fluctuations in data and help identify trends. It is calculated by first finding the metallic mean of the source data and then applying a weight to each data point based on its position in the Fibonacci sequence. The weighted data points are then averaged to create the FMA line. This script allows the user to specify the source data and the length of the moving average, and plots the resulting FMA line on a chart.