I was a bit confused into thinking our `-dev` images had
`root.transient` on, but they don't quite right now because
we don't regenerate the initramfs after installing the updated
ostree in that image.
However, because bootc-image-builder today is throwing away
the immutable bit on `/` (a different bug, see
https://github.com/ostreedev/ostree/pull/3094 ) we actually...
amazingly get a very similar effect in practice!
Anyways, let's go ahead and describe filesystem state here.
c93512c6b1