The leak originated from Weibo and as mentioned earlier should be taken with a grain of salt. The pictures that accompany the leak show the design for the packaging of the OnePlus 6T, with the picture of the inside of the box showing off a much-speculated feature.
As you can see from the above the fingerprint Icon at the bottom of the diagram suggests that, as speculated, the OnePlus 6T will be the first OnePlus to feature an in-displayer fingerprint scanner.
We can also see a “waterdrop” notch at the top of the device which would be the first time this has been seen on a OnePlus phone. This was seen on the OPPO R17 design which tends to be the main source of inspiration for future OnePlus features, so we’re not super surprised but it’s interesting regardless.