

Only the owner of a domain can publish a package attributed to that domain. Otherwise you’d have random hackers publishing malware as an Apache project or something. All you can do is try to contact the owner of the domain and see if they are willing to transfer ownership to you, or better yet, set up a nonprofit LLC, or whatever it’s called in your country, to have it transfered to.
I mean LLC is just a nice option if you want it to be easy to transfer it to someone else next time so they don’t have to go through any hassle. Adding someone to an LLC to have control over the assets is just easier than if an individual owns those assets.
But this all comes down to ownership. Someone owns the rights to the domain. Sonatype obeys that ownership. So it really comes down to how the owner wants to handle it. And in the US anyway, lawyers aren’t really required for an LLC, depending on the state you live in. Many it’s just a couple of simple documents and a small fee. That’s why LLCs are used by rich people to hide their money, it’s cheap and easy. I’ve done it many times in multiple states for various projects and never had any legal background. The nonprofit part is a little more work, but as long as you aren’t bringing in any money, its not necessary. Still easy in practice, but more research to figure out. Also, it comes with a lot of benefits like free access to a lot of stuff, including some from Sonatype. But again, not required, just thinking ahead and how I would do it.
First step would be just to contact the domain owner. If they are no longer interested in owning that asset, then they may just give it to you. If they are unresponsive and the domain is not in use for anything else, you could also contact the registrar and report it and if they can’t contact the domain owner there’s a possibility that they may allow you to purchase it depending on their policies.
Again, don’t get discouraged, and I’m totally willing to give pointers if you decide to go the nonprofit LLC route, but first, just contact the owner and maybe they’ll just give you the login for the domain registrar or if they don’t want to give up the ownership of the domain, maybe just authorize you with Sonatype to publish the artifacts. Essentially, because it’s an ownership issue, the owner needs to be involved.