Another thing I just now thought of - versioning the partition file we keep with the images. We can start out with v1.0.0. And if we change how we store that file, we simply increment the version. This would give us some more flexibility in regard to changes.
Thinking further, the scripts that collect the physical partitions are fine, we can just add JSON output for those.
And really, the LVM describing tools are what needs JSON output, so the effort there is targeted to just those.
I think I’m going to take a swing at adding JSON to an LVM describing tool (there are several).