That’s the bright window on the right side of the altar, exposed and processed to not burn out any of the colors. Did I ever mention we need broad availability of HDR-capable screens. Like, 95% of devices have it?
It already looks pretty good on my Macbook Pro when I turn on maximum brightness. Even real HDR would be possible on the Mac, but for everyone else it would look dull. So, let’s wait another decade 😁