This is fdupes 2.0.0. If you're an end-user then you probably want the file named fdupes-2.0.0.tar.gz. The other archives are created automatically by GitHub and are intended for developers.
Changes from 1.6.1 to 2.0.0:
- Add ncurses mode for interactive file deletion (plain mode still available via --plain or ./configure).
- Add --minsize option.
- Add --maxsize option.
- Add --time option.
- Add --order=ctime option.
- Add --log option.
- Use configure script for installation (Autotools/Automake).