UV-Packer for Blender consists of 2 components that need to be installed
separately: The UV-Packer for Blender addon that provides the user interface in
Blender and the corresponding program that performs the packing.

This archive contains the executable program for UV-Packer.
The latest version of it can always be found at:
https://www.uv-packer.com

In order to use it from within Blender you also need the addon script that can
be downloaded from here:
https://github.com/3d-io/uvpacker-blender-addon/releases

You can find the documentation for UV-Packer with more information about the
installation and usage here:
https://doc.uv-packer.com