This is fdupes 2.3.0. If you're an end-user then you probably want the file named fdupes-2.3.0.tar.gz. The other archives are created automatically by GitHub and are intended for developers.
Changes from 2.2.1 to 2.3.0:
- Add --cache option to speed up file comparisons.
- Use nanosecond precision for file times, if available.
- Fix compilation issue on OpenBSD.
- Other changes like fixing typos, wording, etc.