Is there a modder's guide to the new kind of GUI slider?

[Dunbaratu]

When Breaking Ground came out (or is it KSP 1.7.1?  I got both at the same time and don't know which feature is from which), a new type of part action window slider was invented.

It has two tabs on it that can be slid to select a min/max value that gets applied to another slider's range limits.  The servos use this to select the range the "target" slider covers.  And I suspect that needing to understand this new kind of GUI widget is going to be required for me to support the new parts in kOS, since the values of the slider's minValue, maxValue, and stepIncrement are not correct for these sliders if I read them the old way.  I need to understand how the GUI knows to ignore the range.minValue, range.maxValue, and range.stepIncrement for a slider and instead apply another slider's tab ranges to do that.  I assume there's a systematic rule for how it all works, and for now I'm trying to work it out by trial and error.

I can imagine it would be nice for other modders too to know how they can make their own such tabbed sliders, and how they should set up their Attributes to tie them together.