code: func (m ManifestList) References() []distribution.Descriptor {
  	dependencies := make([]distribution.Descriptor, len(m.Manifests))
  	for i := range m.Manifests {
  		dependencies[i] = m.Manifests[i].Descriptor
  	}
  
  	return dependencies
  }
docs: // References returns the distribution descriptors for the referenced image
  // manifests.