As stated by kujuman 20 Apr 2016 here http://forum.kerbalspaceprogram.com/index.php?/topic/77062-11-navutilities-ft-hsi-instrument-landing-system/:

Software License:  2014-2016. All rights reserved.
Permission is granted to any current, former, or future members of the KSP community (e.g.; non-professional modification makers and forum members) to update, maintain, use portions of the code, and/or release derivatives provided that 1) the new work is solely to be used as a modification for Kerbal Space Program (and future versions thereof) and 2) the new work is freely distributed and may not be sold or exchanged.
Artwork License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License 