Very interesting indeed! And thank you for raising awareness!
There’s another similar project that’s still WIP and that hasn’t received a lot of development recently. Though, its maintainer does provide hardening scripts for Fedora’s Atomic distros that are worth looking into. Hopefully, we might even expect a collaboration of sorts between these projects early next year 🤞.
This wouldn’t sit well with most privacy conscious folk out there. Though, I can understand it from a security point of view. Especially, when one notices that Chromium isn’t installed from Fedora’s repos, but instead the RPM is built to offer a more up-to-date version that should provide improved security compared to the stable version.
Probs for the sake of disabling unprivileged user namespaces; as you might have correctly alluded to.
I imagine for the sake of minimizing attack surface.
The Nix package manager is installable on Fedora’s atomic distros, so perhaps that route is worth exploring.
To my knowledge, Flatpak’s sandbox indeed isn’t achievable by default with RPMs; unless one knows how to properly utilize SELinux to that effect.