Docker Hub - pull fake image

Question

I trying to play a bit with the Sigstore's cosign tool. The tool is signing the image and then uploading the signature to the same repository.

So if I have a tag - tool:latest and I sign it, the tool creates a new tag named - <digest_of_latest>.sig

I want to somehow download that tag's data, but if I try to docker pull - I get an error that docker cannot load the image (which is right, this is not real image).

is there a way to download the raw data file from the docker hub repository ?