RGB

RGB represents color using red, green and blue components. The three component values need a defined color space to identify an actual color; the letters alone do not specify the primaries, transfer function or precision. Apple’s color-space overview

BetterDisplay uses RGB in two contexts worth distinguishing. Color Mode can identify RGB as an output encoding. Separate red, green and blue controller adjustments change the balance of the channels.

Changing a channel adjustment is not the same as choosing the output encoding. See Color mode and Color space for those concepts, or Color Mode for the encoding interface.