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.

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.