This section from the docker spec seems to have been dropped: https://github.com/docker/distribution/blob/5cb406d511b7b9163bff9b6439072e4892e5ae3b/docs/spec/api.md#cross-repository-blob-mount

I see that some info is still present in detail.md, which isn't referenced by spec.md at all: https://github.com/opencontainers/distribution-spec/blob/master/detail.md

Was this omission intentional?