This was changed back when OpenColorIO was introduced around 2.64.
Color space is now controlled in the data block settings for each input image or clip, and in the scene's color management panel.
I'll remove the references to the color space controls.
And to deal with the out of date images, and better comply with doc guidelines, I'll remove the examples completely.
this is different things. Color management in all scene. And keying by difference between two images by R,G,B parameters, or HSV, difference between values of each channel. this is useful function.
But noe we can key by average value only, i don't understand, why we was delete it.