You're probably right. I just want what's advertised: software that uses web standards to interact with servers on my behalf. Idk where this feature lands on that scale. This seems like a pre-browser-extension sort of feature that is obsolete now.
I don't know if it's objectively stupid, but the surprise I experienced discovering that my browser has a bunch of hacks built in to fix external website problems lowers the trust I have in Firefox.
Any device can decide to set it's own IP so that's not too far fetched. Have any IoT crap like a water softener or colorful lights or speakers or cameras?
This made me laugh