This is how it always is with Firefox, you hit some bug and then find that it was entered YEARS ago, while they burn focus on things like Pocket.

It’s more that it wasn’t prevented back when the web was first coming together, because security wasn’t on almost anyone’s minds at all. There wasn’t a hole added at some point; it’s just that browsers didn’t specifically block domains that resolve to public IPs from accessing domains that resolve to private IPs.

Realistically, it’s a backdoor to every network firewall that has existed for the entire era in which browsers were used in “secured” internal networks also connected to the internet. Everyone has either designed with it in mind, or gotten lucky that nobody tried to use it on them for like 30 years. I think it’s good to put away this footgun, but there’s no useful blame to assign here.

I'm hazy on the details, but:

Home Assistant has a well-known public name that opens your local instance. On first access, you need to give it the name or ip of your instance, which is saved in browser storage. This supports deep links into your config from forum posts.

My mum also had a shitty D-Link wifi mesh device, which was packaged as an appliance. I cannot speak lowly enough about that garbage device, but then, I am not really the target market. iirc it had something similar; a public dns name for local appliance mgmt.

I wonder how bad does Mozilla have to be that you have to continue using Chrome without ublock?

I'm curious: What's your reasons for not wanting to support Mozilla?

Soon, you won't be able to install it locally because the API it relies on will no longer be available. Use Firefox.

then again, if the makers of one big browser (and via there also the derived browsers) start force-shoving spyware upon you (by restricting blockers), it comes down to a decision of how you set your priorities. Personally, It's a clear cut red line, but you do you.