See later discussion on narrow range and full range

===========

This can be tested in WPT by converting full-range sRGB values to one of the common encodings (such as 2100 PQ, 2100 HLG, Display P3, linear sRGB) and making a PNG with those values and the appropriate cICP chunk. A pass displays the same colors as an sRGB reference image.

For non-browser support, detecting and correctly decoding the chunk demonstrates support.