systemd doesn't support anything but Linux, as it is designed around Linux-specific APIs.

OpenBSD uses a really simple rc.d to get going:

* https://www.bsdcan.org/2016/schedule/attachments/337_bsdcan-...

*YES*, systemd is an option. It is not the default.

https://lobste.rs/s/jx3cr6/initware_systemd_fork_runs_on_ope...

I'm the first to admit that I'm ignorant of the facts here, but seeing that a systemd fork ran on OpenBSD for the first time two months ago does not give me confidence that it's "an option" in the sense that you can trust it to work well.

And to be pedantic (this is an OpenBSD thread, after all), it's not "systemd", it's a fork of systemd called "InitWare", and the GitHub repo describes it as "alpha software".

Someone also pointed out in the discussion you linked that it doesn't seem to include journald. Here's a relevant PR: https://github.com/InitWare/InitWare/pull/27

Pretty much this. SystemD was inspired by LaunchD on MacOS and was written as a clean room implementation of something in the spirit of LaunchD. InitWare is essentially an init system inspired by SystemD.

They all borrow one from Slackware Linux.

Is this a joke or is there some interesting tidbit here? Both?

definitely not.