System daemons frequently require private runtime directories below /run to store communication sockets and similar. For these, is is better to use RuntimeDirectory= in their unit files (see systemd.exec(5) for details), if the flexibility provided by tmpfiles.d is not required.
ah, more systemd cruft. No wonder it is so difficult to figure out
Does that imply that openrc has a similar mechism and global variable that one can define in the /etc/rc.d directory?