The examples for pulling and pushing an image use docker v2 schema 1 images, e.g.

https://github.com/opencontainers/distribution-spec/blob/fb183ce74113c89a64b55ef2d877277268f9a8af/spec.md#pulling-an-image

https://github.com/opencontainers/distribution-spec/blob/fb183ce74113c89a64b55ef2d877277268f9a8af/spec.md#pushing-an-image-manifest

https://github.com/opencontainers/distribution-spec/blob/fb183ce74113c89a64b55ef2d877277268f9a8af/spec.md#on-success-ok-3

https://github.com/opencontainers/distribution-spec/blob/fb183ce74113c89a64b55ef2d877277268f9a8af/spec.md#put-manifest

Similarly we have a lot of references to signatures that aren't part of the OCI image format.