Safariland als has a thumb button that releases a locking mechanism that latches into the ejection port. Won't be able to see it unless you are looking for it.
Bladetech WRS has a spring loaded hood that is released by a thumb break. A lot more obvious.
There was no hood or thumb snap on this holster I remember seeing. The holster retention device I remember seeing was between the handgun and the body. The retention device looked like a a piece of plastic, almost looked like a straw. You would press it down to get the handgun out of the holster. You couldn't tell it had any retention device unless you were the one wearing the holster.
Now I'm going to go nuts if I don't find it. I know what my task for the day is.
As far as magazine disconnect, how do you relate that to retention?
The magazine disconnect is now being incorporated into the firearms retention training with law enforcement. Like I previously stated I disagree with it being incorporated into handgun retention.