Patched vs Stable install images/iso

[shep]

It looks like NetBSD is developing numerous versions of install images.
From README

The current build list is as follows:

HEAD - The main trunk of the NetBSD source tree
netbsd-5 - The branch tracking the 5.0 release branch (to become NetBSD 5.2)
netbsd-5-0 - The branch tracking the security/critical fixes for NetBSD 5.0
netbsd-5-1 - The branch tracking the security/critical fixes for NetBSD 5.1
netbsd-6 - The branch tracking the 4.0 release branch (to become NetBSD 6.1)
netbsd-6-0 - The branch tracking the security/critical fixes for NetBSD 6.0

But what is confusing me is netbsd-6 contains images denoted as "STABLE"
eg: 'NetBSD-6.0_STABLE-amd64.iso'
while netbsd-6-0 denotes the images as 'NetBSD-6.0.1_PATCH-amd64.iso'

I am assuming the 4.0 is a typo.

It seems these are backwards. If I wanted to try NetBSD 6.0 with security/critical fixes I would assume this to be stable. If I wanted new features the PATCH connotation seems more appropriate. But then again, I thought stable in FreeBSD meant "stable"

Any NetBSD guru's have any insight?