What the heck is /pkg?

So they might be aiming for their own brew? Or is there some expectation for a different thing altogether?

> It’s also not clear what the “pmk” in /etc/paths.d/10-pmk-global refers to.

Maybe package management kit, if we go by recent Apple naming conventions.

> I only started looking into this when I noticed an unfamiliar entry starting with /pkg in my PATH. I assumed something had gone awry. Then I saw that there was, indeed, a /pkg directory in the root of my filesystem. [Emphasis mine —JvD]

See, that's your problem: you think of it as your PATH and your filesystem. But it's actually Apple's and Apple's macOS's filesystem and PATH variable. They may allow you to use those to e.g. store your data and operate on it, but mostly it belongs to them, so they arrange it as they see it better fitting them. And of course, they don't really owe you an explanation of their design decisions, especially such non-user facing ones.

May or may not be /s