"DOCKER_CONTENT_TRUST=1 docker pull ..." results in error "notary.docker.io does not have trust data"

Not sure if this is by design, but there's no signing of the nvidia docker images by notary.docker.io. It's not critical for me at this time since I can see the originals here on gitlab, but would be nice to know if signing the images for notary.docker.io is something that's planned or not to be done.

$sudo DOCKER_CONTENT_TRUST=1 docker pull nvidia/cuda:11.0-base-ubuntu20.04

gives

Error: remote trust data does not exist for docker.io/nvidia/cuda: notary.docker.io does not have trust data for docker.io/nvidia/cuda