Checking out the initial request on github for this feature I wonder why is this necessary? What access to the local network does the browser provide, or need to provide, and why isn't this something developers are more concerned about? I had a feeling this was possible as I see lots of mdns requests when I connect to certain things running sockets.

https://github.com/uBlockOrigin/uAssets/issues/4318

There are certainly use cases, but whether they’re warranted is a good question.

One popular router maker offers a ‘magic URL’ (domain name) that scans your network for the gateway management page, and redirects. It’s not necessary, but it certainly helps novice users. Having worked in IT support,

I’ve also purchased hardware devices that have a web management UI; which connects directly instead of proxying through a cloud.

Ultimately this is probably one thing that should be behind a permission request (like webcam access), but it’s not a feature without value.

It's being looked at.

https://bugzilla.mozilla.org/show_bug.cgi?id=1481298