Can’t find .plist files
~/Library/Containers/com.apple.Preview/Data/Library/Preferences/com.apple.Preview.plist


and

~/Library/Containers/com.apple.TextEdit/Data/Library/Preferences/com.apple.TextEdit.plist


~/Library/Containers does not seem to be indexed, at least on my system, so mdfind didn't find them. That said, I have a copy of my system on another hard drive, which IS fully indexed, and it listed some files there that started me poking around in that folder on my OS drive.