Comment 7 for bug 1593657

OK. I did just a bare minimum checks.
The file is called mux.c, the function is "void muxserver_listen(void)" at line 1241.
Two comments seem quite important:

        /*
         * Use a temporary path before listen so we can pseudo-atomically
         * establish the listening socket in its final location to avoid
         * other processes racing in between bind() and listen() and hitting
         * an unready socket.
         */

and

        /* Now atomically "move" the mux socket into position */

Unluckily I haven't enough time to go on. Maybe later...