What is the purpose of the add-credential form on the home/index page?

[pedz]

I go through the process of creating a registration and it redirects me back to the home page where I am now logged in but there is a form "New Security Key nickname". I've not be able to give it anything that it likes and I can't even figure out what it might be fore.

Thank you for the repo. I'm trying to adapt it to Rails 7 which is hard for me because I'm such a newbie but I'm sure the repo is making it far easier than it would have been otherwise.