That does not belong to the DMV of any state. Have you visted the DMV site for your state?
As an example, here is California [1] It seems Wyoming uses .us and no https. [2] Nevada uses .com but at least has https [3] Now I am curious how much deviation each state has. They were supposed to follow the pattern www.dmv.[state].gov. Something went off the rails it seems.
And for everyone's complaining (and I had felt it in other states) I have to say the Florida DMV isn't that bad. I've rarely waited even in person more then 20 minutes, I have been able to do most things online for quite a number of years and their site while not great isn't horrible. Don't get me wrong, it could be better, but just I've not had the nightmare DMV experience with Florida that people equate with big states.
And to your point on URL's I don't think there is any real pattern. https://www.flhsmv.gov/ is Florida's state level DMV and counties have their own separate sites for local tag/tax offices.
[1] - https://www.dmv.ca.gov/portal/ [california dmv]
[2] - http://www.dot.state.wy.us/home.html [wyoming dmv]
[3] - https://dmvnv.com/index.htm [nevada dmv]