For very deep historical reasons, the canonical value for system color was handled by multiple scripts (_foundation and _arabesque) and could also be affected by _ambiance after 8.0.4 because of the post-TP flashing effect. Support for the wavelength HUD has continually atrophied since 8.0 came out because it works by directly sending a light bus message instead of the more polite system command approach. 8.5 will probably need an updated color-tweaking HUD.