We have a use case in Image Builder / osbuild that requires transferring a container and its manifests (and particularly the manifest list) using a portable format that doesn't affect the image itself. We also don't want to be downloading all the images for all the architectures just to get the manifest list. In the end, it should be possible to run the container by referencing its manifest list digest without needing access to the original registry (or even an internet connection).

Currently, based on rhn-engineering-mitr recommendation, we are using --multi-arch=index-only to store the manifest list in a dir: and copy it into a single-image dir: downloaded separately.

It would be very useful if we could copy a single image (or a subset of all the images) and preserve the original manifest list so that once we copy a container to local storage, we can refer to it by the original manifest list digest that we used when downloading from the registry.

Upstream issue: https://github.com/containers/skopeo/issues/1935
Related Image Builder ticket: COMPOSER-1898