The standard supports a repository_url "qualifier" (query parameter)[0], which can be used to override whatever the default registry is (which, for Docker, is hub.docker.com[1]).
>There's even a generic type as a catch-all for things that don't fit an existing ecosystem (for example, a proprietary or legacy component) or for ecosystems that build custom distributions, such as yocto or buildroot. We should note, however, that SBOM and software composition analysis tools vary widely in their ability to understand generic PURLs, so we do recommend you talk to your current (or prospective) vendor if this is an important feature for you.
