This makes it explicit at compile-time that these fields should not be reassigned outside the constructor.
The files and folders here are not owned by Duplicati. Each folder has a "license.txt" file that describes the license for that item. Each folder has a "download.txt" file that contains a link to the page where the files were originally downloaded. Each project is belived to be open source and the files present here are unmodified binaries, unless stated otherwise in the respective folders.