I’m a bit surprised that they mentioned “distribution” on the Bluefin website, as the Universal Blue site (the base project behind Bluefin) explicitly mentions not being a distro - and I know that Jorge tends to be very clear that they’re not building a distro:
This isn’t a distribution, you can always rebase back to Fedora without reinstalling. This is a unique relationship between upstream and downstream that is popular in cloud, but still new to the Linux desktop. “Custom images” seems to be a decent place to start since that’s what people call them in cloud.