ICANN approves use of .internal domain for your network
https://lemmy.world/post/18404910

ICANN approves use of .internal domain for your network - Lemmy.World
Browsers barf at non https now. What are we supposed to do about certificates?
If you mean properly signed certificates (as opposed to self-signed) you’ll need a domain name, and you’ll need your LAN DNS server to resolve a made-up subdomain like lan.domain.com. With that you can get a wildcard Let’s Encrypt certificate for *.lan.domain.com and all your https://whatever.lan.domain.com URLs will work normally in any browser (for as long as you’re on the LAN).
Right, main point of my comment is that .internal is harder to use that it immediately sounds. I don’t even know how to install a new CA root into Android Firefox. Maybe there is a way to do it, but it is pretty limited compared to the desktop version.