https://github.com/stac-utils/pystac/blob/e713adf4335b2548fc2ba06b9dab9393dda18c44/pystac/media_type.py#L25 The current ZARR media type value does not conform to recommendations for media types. There are two issues: 1. Convention is application/vnd.{vendor-specific-part}, not just `vnd` 2. the `+{other type}` is only used when the media type is a more specific version of another media type, like `+json`, not when it's a "new" format itself.