The first is WebGL, which provides a way for web developers to access the low-level graphic capabilities of the computer or device that the browser is running on.
Following each flail, a clear graphic representation of your stroke path along with several key stats will display on your device: the critical putter-face angle at impact and tempo, among others.
As you can see by the photos, the design of the device is largely similar to those we've seen, but the graphic on back is slightly different, and that piece of tape is covering a QR code (how very Google of them).