Oh how I wish I had access to this summary a few months ago! Ah well, I have slowly pieced together the puzzle pieces from conversations and web links, but this summary from the Guardian’s Science editor Ian Sample pulls together all the answers. And helpfully fills in a few knowledge gaps still gaping for me.
Here’s the link: https://www.theguardian.com/technology/2019/jul/29/what-is-facial-recognition-and-how-sinister-is-it?CMP=Share_iOSApp_Other
