Right now, after RHEL branches from Fedora, it's disconnected — basically a fork more than a branch. This provides a public upstream for the RHEL 8.y branches.
Atomic Host is being retired.
CoreOS has two branches, one which is part of OpenShift (RHCOS) and Fedora CoreOS. That's very different from the RHEL model, so it doesn't directly map.
Sure. That became Container Linux. Now we have Fedora CoreOS, which combines tech and ideas from both Atomic Host and CoreOS/Container Linux. It uses Fedora packages but through rpm-ostree, not with the yum/dnf system you might be used to.
Since CentOS Stream and Fedora brances will exist in the same git system, I can see future Fedora CoreOS making use of slower-moving CentOS Stream branches where useful. But that's all to be worked out.
More or less what I got as well. This is a welcome change for ISVs and IHVs, and I’m glad to see CentOS have a place in the family beyond “RHEL for people who don’t want to pay for support”.
Atomic Host is being retired.
CoreOS has two branches, one which is part of OpenShift (RHCOS) and Fedora CoreOS. That's very different from the RHEL model, so it doesn't directly map.