The IP or Unix socket can be accessed by any local user (e.g. a Unix socket that accepts all local connections, or an IP socket listening on 127.0.0.1 (or ::1) or rejecting connections not from that address).
The associated variant must be ignored. For a D-Bus tube, this means that the "same user" access control typically provided by default in D-Bus implementations SHOULD be disabled. If the socket is only available to local users (e.g. a Unix socket, an IPv4 socket bound to 127.0.0.1, or an IPv6 socket bound to ::1), the ANONYMOUS authentication mechanism MAY be enabled.