Maybe it's my reading of it, or my misunderstanding of the possibilities,
but I've always seen a Config section in a Manifest to be a pointer to the
config blog. But the definitions here say:

Manifest: a JSON document which defines an Artifact. Manifests are defined under the OCI Image Spec apdx-2
Config: a section in the Manifest (and associated Blob) which contains Artifact metadata

It would seem more accurate to me to say that a Config is a blob, referenced
from a Manifest, describing that manifest.