Going to the Set Up page, I was able to find a section for my remote. However, Logitech now wants you to download desktop software called MyHarmony that is only available for Windows or Mac machines. Clicking on a box that says "Looking for the old sign in page?" brings up the following message:
So it looks like Congruity may no longer be of use since it is not possible to generate the Harmony remote configuration files from the website.
Therefore I am putting this configuration step off until I install my Windows 10 VM. Didn't I say "goodbye to Windows 10" earlier? I meant I'm putting Windows 10 where it belongs. In a virtual machine.