"local ip address", not localhost. They're doing file sharing on the local network. This also means that the common 'install a custom root for localhost' https

"local ip address", not localhost. They're doing file sharing on the local network. This also means that the common 'install a custom root for localhost' https trick won't work because it's machine-to-machine communication - https everywhere specifically stops machines from communicating locally. You could probably hack it with a relay server but at that point, why bother?