These are the directories under /usr/pkg on NetBSD based upon packages I installed. But setup depends upon OS and the person who set it up. I never heard of inv, maybe inv is a mac thing.
bin | include | pkgdb.refcount
dict | info | pkgsrc
etc | lib | qt5
gcc12 | libdata | qt6
gcc14 | libexec | sbin
gcc16 | man | share
gnu | pkgdb | tests
On NetBSD /var used for logs other data. But I suppose someone could configure under 'pkg' if they wanted to,
Probably not, then. The /pkg hierarchy on macOS doesn't look like that at all - there's no /pkg/bin, only /pkg/env/global/bin, where /pkg/env/global is a symlink to a subdirectory of /pkg/inv/envs.