Set up a new home-assistant green. It was lovely to plug it in and just see it boot and come up. I found its IP address and attempted to connect but got nothing but a “This site can’t be reached” page. Ok, fine, go back, re-read the instructions, see that :8123 hiding there.
HA Green is aiming to be more of an appliance than a tinkerer’s device. Hosting a web UI on port 80 is the default. Devices that spin up their own UI for initial configuration should work if you point a web browser at it, without having to override a custom port.
A brand new HA Green should listen on port 80. Doing so will remove one small barrier to entry. (Sure, it can also listen on 8123, and why not, 443 too. Make it easier for someone who’s just gotten their first HA in the mail get started.)