This software is documented in the Journal of Structural Geology article:
"Fold Geometry Toolbox - Automated determination of fold shape, shortening, and material properties"
by Marta Adamuszek, Daniel Walter Schmid, and Marcin Dabrowski.
FGT is a program to analyze fold geometry in 2D. This toolbox estimates amount of shortening and mechanical properties of folds using four parameters: arc length, amplitude, wavelength, and thickness. FGT is capable of dealing with noisy interfaces and complex fold geometries.
Thanks for the comment. The paper is now available on line.
This looks interesting for the specialized group for which it is intended.
The paper in question has not been published as of this date, and the toolbox requires at least three other files (but is written to prompt the user for automatic download and installation from the FEX if these are not present).
I won't assign a rating until I can read the original paper and have time to examine the toolbox in action - however it appears to be well-coded and thoroughly commented.
Minor corrections related to the Fletcher and Sherwin method.