This is useful when converting your Styles to Variables, and wanting to create a hierarchy across collections by using Aliases (references) from one Collection to another.
This will simply match hex values from one collection to another and create an alias if there's a match, so you can have a Collection of Primitives that other Collections reference.
The plugin is not yet published on figma.com/plugins so the installation process is a little more involved right now.
1. Download or clone the contents of the GitHub repo to a location that is not your downloads folder (if you delete these files after installing through the Development menu, it will break the plugin)
2. Right-click the canvas Plugins > Development > Import plugin from manifest…
3. Navigate to the file /path/to/plugin/manifest.json
4. This panel will close and the plugin will now be available by going to the Development section in your plugins.