What the heck is /pkg?

Recently, while troubleshooting a PATH issue, I noticed an entry for /pkg/env/global/bin. At first, I worried that something had gone horribly wrong. Turns out, this is part of macOS 27.0… though no one is sure what it’s for yet. First, some background. Since Mac OS X 10.5 in 2007, the OS has included a path_helper utility. This reads entries from /etc/paths as well as from any files in the /etc/paths.d directory. While one could potentially take advantage of this system, I (and I’d guess most others) handle adding new PATH entries using the .zshrc file, or similar. It’s primarily used by Apple. In macOS 10.15, an entry was added to /etc/paths.d to support the new location of the rvictl utility. In macOS 13.3, Apple added some new entries to support Cryptexes. Now in macOS 27.0, there’s a new 10-pmk-global file 1 which adds /pkg/env/global/bin to the PATH list. I only started looking into this because I was troubleshooting a PATH issue. There was an unfamiliar entry starting with…