Curious. What is the use case here? I’ve spent tens of thousands of hours of my life on the Internet and a lot of that as a sysadm and I’ve not once heard of people accessing or linking to sites this way.
Personally, I just want to properly handle this edge case and it would bother me if my sites didn't handle it correctly. There are advantages for using FQDNs since they are not ambiguous there are extra optimizations that can be done. I don't want my sites to be problematic for people who want to use them so I make sure my sites properly handle them. Usually handling FQDNs is easy as it just works out if the box on most server software.
Can you provide a URL to a page containing a link of this style? I’ll concede that it’s useful to someone if I see it! The term ‘FQDN’ does not always imply the dot at the end?
If you want a link to a page with a link like this you can click on the github issue I referenced in my original comment as there are links there like that.
If you want a more natural page that is less meta with such a link