Apparently the 'silent patch' dealt with Gatekeeper specs and thus applied to OS X well beyond the Lion version.
Gatekeeper is a security feature first implemented in Mac OS X 10.8 (Mountain Lion).
So most of this discussion is beside the point with respect to Mac OS X 10.7 (Lion) and earlier versions.
Apple's first silent update was in 2014 and there have been some for
10.6.x that involve Apple's antivirus XProtect. What's not clear to me is if these silent updates are the same as
Security Updates, which can be turned off (see the link).
I also could not determine when the silent ones take place. Usually Apple requires an Internet connection and a period of computer inactivity (how much??).
