Good view of Tach
I'd say that redline starts around 6300, and then gets 'redder' at around 6800. You can see the redline, and then a red crosshatch stripe under it starting around 6800, so maybe it's Tapshift related? IIRC it doesn't automatically shift if you're in M and forget to shift. They also could have bumped the redline for the tapshift..
Anyone also see that the redline actually stops and turns back to white a couple notches before the needle buries itself? Must be GM telling you that the L99 is going supercritical..