>>123
呆れたな。だから説明読めよ。
http://www.NetBSD.org/Releases/release-map.html

Formal release

An official, believed to be reliable, source and binary distribution of
NetBSD. This can either be in the form of a major release like 2.0 or 3.0,
of a maintenance (stable) release such as 2.1, or a security/critical
release like 2.0.2.