After a bit more code review, the
SaturatedOpacity value in the sidecar file seems to correspond to:
Color -> Color Toning -> Opacity
-> Saturation Protection -> Strength slider/field entry
SaturationThreshold would be the other parameter in that group. The mix of camelCase, PascalCase and lowercase can get a bit confusing at times...
Based on this line in the source code:
saveToKeyfile(!pedited || pedited->colorToning.saturatedopacity,
"ColorToning", "SaturatedOpacity", colorToning.saturatedOpacity, keyFile);
I'm gonna guess it's related to the Opacity subsection in the Color Toning section under the Color tab. The variable is a
bool, and it's a member of a structure called ColorToningEdited, so it's probably just an indicator to look for and/or use/ignore some other variables that contain the customized curves, etc. that make up the rest of the settings in that part of the module.