Currently, if a user wants to proxy library content through Quay from Docker hub, they must explicitly mention the library namespace. For instance, if docker is the organization through which we're proxying Docker Hub content then downloading any library image through Quay needs to look like this:

podman pull QUAY_HOSTNAME/docker/library/mariadb

This also causes Quay to create a repo called library/mariadb instead of just mariadb. Proposition is to automatically append the library namespace on any pull through Quay that doesn't have an explicit upstream namespace attached:

podman pull QUAY_HOSTNAME/docker/mariadb:latest

If an upstream namespace is added to the request, then we do not append library:

podman pull QUAY_HOSTNAME/docker/some_namespace/mariadb:latest

It seems that other registries do have this ability:

Harbor PR: https://github.com/goharbor/harbor/issues/12719
ECR request: https://github.com/aws/containers-roadmap/issues/2260

Thank you!