Quick Answer: The color codes provide an indication for the conventionality of that knob's respective setting from a Western listening habit for this particular chord.
Color codes in rim of knobs in Liquid NotesLiquid Notes performs a harmonic analysis when you open a project that enables it to understand the correlations between notes, identify chords, etc. It also ranks chords and their respective setting for chords and tension on a virtual scale for resynthesis. This ranking ranges from ordinary chords (=conventional) to very unusual chords (=unconventional) from a Western listening habit.
The color code in the rim of a knob then correlates with the degree of conventionality for the particular setting of this chord, ranging from green to red.
We included these indications to give you a better visual aid when making changes to chords.