Just out of curiosity, what is /usr/share/defaults/swupd/format for ?
I kind of know that this points to https://cdn.download.clearlinux.org/update/version/format28/latest which tells swupd about the latest version of clr linux.
But there is also cdn.download.clearlinux.org/update/version/latest_version. Why doesnt swupd use this file to determine the latest version of clr linux ?
swupd formats versions are a mechanism to internally tag points when something changes that that might break OS backwards compatability or make it too complex to address. For example, a change to the manifests format swupd uses.
swupd formats are not CL versions. There is a current / latest pointer to the newest CL version on the downloads page.