This is a Macbeth color chart calibrated with data published by BabelColor (https://babelcolor.com/index_htm_files/RGB%20Coordinates%20of%20the%20Macbeth%20ColorChecker.pdf). It is optimized for both Cycles and EEVEE.
Very nice, using the BabelColor data makes this a lot more trustworthy for anyone doing color critical work or trying to match footage between Blender and real cameras. Having it optimized for both Cycles and EEVEE is a big plus, since you can keep a consistent reference chart no matter which render engine you are testing in. If you are interested in systematic workflows and repeatable setups, some of the strategy focused material on https://ignitioncasinous.com/ can be unexpectedly useful for thinking about consistency and evaluation.
Thank you!