Hi. A while ago, I switched back to Silverblue again and this issue came up with it.
I am using flatpak version of Firefox and when I try to go a local server (specifically a Raspberry pi for my 3D printer) by their name, it cannot resolve the address. I can ping that domain name on the terminal though. On Firefox, I can only use the IP address of the machine. This was not the case when I was using Workstation.
Firefox has 2 methods to isolate processes from another.
Browsers are doing extremely dangerous stuff every day, running random Javascript every day.
So sandboxing is really important. When sandboxing the entire browser with flatpak, the one part of the sandbox is simply broken, so Firefox just disables it and pretends that would be fine. Which it is not, otherwise there would be no reason for it to exist.