Is it possible Occulus has a big need for such an OS and this is the cause of the contributions? Or is this Carmack being a hobbyist and simply making contributions for its own sake?
John Carmack stepped down as consulting CTO of Oculus in November 2019.
Nit: In November, he stepped down as CTO. He still has a part part-time role at Oculus with the title of 'consulting CTO'
I assumed his use of an armadilloaerospace address was a signal that it isn't work-related.
He's basically retired at this point and working on things he finds interesting (which was AGI as of a few months ago; there was a blog post where he went into more detail).
Or perhaps he's bringing Armadillo Aerospace back and wants to use OpenBSD for guidance and control?