Harbor v2.0 supports OCI images and OCI image indexes (https://github.com/opencontainers/image-spec/blob/master/image-index.md). An OCI image index (or OCI index) is a higher level manifest which points to a list of image manifests, ideal for one or more platforms. Both the index itself and the images referenced within are called artifacts in Harbor. An OCI index can hold another OCI index and so on. For any artifact referenced by an OCI index, the referenced artifact is known as the child artifact and the OCI index referencing the artifact is known as the parent artifact. The child artifact belongs to the parent artifact or is a part of the parent artifact.

You can add as many tags to any artifact as you want without impacting the artifact digest or the associated storage. For an OCI index, you can add tags to the parent as well as add tags to the individual referenced artifacts within. Tags added to the parent artifact are not automatically inherited by the child artifacts.

In the Harbor interface, click on an artifact to see its current set of tags. To add a tag, click ADD TAG, specify a name, and then click OK.