What do we know about how open source software becomes eligible for the Docker Hub library?
From https://docs.docker.com/docker-hub/official_repos/


  Docker, Inc. sponsors a dedicated team that is responsible for reviewing and publishing all content in the official repositories. This team works in collaboration with upstream software maintainers, security experts, and the broader Docker community. While it is preferable to have upstream software authors maintaining their corresponding Official Repositories, this is not a strict requirement.