Password Protected Snapshots

I tend to download my snapshots after creating them in case the SD card in my PI dies… I have noticed however that with password protection enabled I was not able to quickly open the snapshots… in something like 7zip (first level opens but the gz files don’t prompt for password etc).

What mechanism is used for the password protection… If my whole system died and I just wanted to pull the config out of a password protected snapshot how could it be opened with external tools?

Also wondering this.