

Download these files to a temporary folder and them copy them into the Plug in folder in TheGIMP.
The Plug in folder can be found in the following directory:

You need to restart The GIMP before the new Plug in is loaded. You can access the new Plug in by Opening an Image in The GIMP and then choose Image >Separate and choose one of the options from the menu.
Visit the Color page and install the ICC Color profiles to make these Plugins active.