netgroup(5) on OpenBSD
The text 1edd5888fb1a, as OpenBSD 5.8, OpenBSD 5.7, OpenBSD 5.6, OpenBSD 5.5, OpenBSD 5.4, OpenBSD 5.3, OpenBSD 5.2, OpenBSD 5.1, OpenBSD 5.0, OpenBSD 4.9, OpenBSD 4.8, OpenBSD 4.7, OpenBSD 4.6, OpenBSD 4.5, OpenBSD 4.4, OpenBSD 4.3, OpenBSD 4.2 shipped it.
defines network groups