"This repository has been archived by the owner on Oct 6, 2023. It is now read-only."

According to https://github.com/jbruchon/jdupes/commit/2984bd77f4712359, it's at https://codeberg.org/jbruchon/jdupes now.

Another option is duff: https://github.com/elmindreda/duff

That’s much faster, and I use that too, yes.

Yup I use jdupes and it's way, way, way faster than fdupes.