This does seem to be very specific to Game Maker though. Like saying 0.0-1.0 is 8 bit unorm is incorrect. It's just a unorm, no bit depth is otherwise implied. Similarly HDR doesn't mean exceeding 1.0. It can mean that, but if you're going to a display directly you're going to want something more like 101010X2 unorm in PQ, which is still 0.0-1.0 in the fragment shader

Going of on tangent asking this but have any games ever shipped with colour charts for calibration with different monitors?

Nice succinct article. Thanks.