What do you connect to, when you connect to varlink, if there is no broker service?

It's kinda weird to present this as a DBus alternative when it doesn't even offer the same facilities, particularly many-to-many communication.

Though I have a pretty good idea of where a Varlink broker would turn up and which init system it would be tied to.

Very typical systemd–developer style.

Those are pathname UNIX domain sockets, so you address them through the socket file, which is conventionally stored somewhere under /run.

You can run "netstat --listening --unix" to list the UNIX domain servers on your system, to get an impression.

See https://man7.org/linux/man-pages/man7/unix.7.html

And what does the socket connect to?