It has been Slackware based since inseption I think just because that’s what fit when it was created.Fedora particually Silverblue and in turn some of the Ublue projects have shown you can create a super stable environment for container based workloads.
Updates are seemless and targetable a fedora backend gives them an easier switch to podman should docker not be viable in the future.
From the article it looks like they’re focusing on Faster security updates Better hardware support through the Linux kernel There’s a clear seperation of the base os and the apps,plugins etc that Silverblue/Ublue can offer that Debian couldn’t do as easily and they’d be better off just sticking on Slackware.
Still rocking my fractal R3 nothing beats it for disk space and sound proofing