That's not entirely true. PAM exists on many systems, wiyh their own codebase. FreeBSD for example has its own build which definitely doesn't presume Linux. No

That's not entirely true. PAM exists on many systems, wiyh their own codebase. FreeBSD for example has its own build which definitely doesn't presume Linux. Not sure which one macOS' implementation is based on but considering its history I would bet on one of the BSDs.