Gentoo Linux has /var/run symlink’d to /run. Has been this way for a while I
think (since 2015 when /run was added?). I think /run is the preferred, and
the link is for compatibility.
Looks like Arch Linux is doing the same thing (found this while looking for the
Gentoo history):
https://wiki.archlinux.org/index.php/Tmpfs
<https://wiki.archlinux.org/index.php/Tmpfs>
And it looks like it dates back to 2011 and was caused/changed for systemd/udev
(part of systemd):
https://lwn.net/Articles/436012/ <https://lwn.net/Articles/436012/>
So most/all OS’s that support systemd have /run configured this way?