Technical information about 'Highlight Recovery'

I'm looking for deeper understanding of what the Highlight Recovery mode in the Raw Tab does.

The excellent manual says:

Highlight Recovery: A checkbox that lets you include additional highlight sensor data that’s usually clipped by the standard decoding matrix. In cases where you have extremely clipped peak highlights, you may obtain additional image detail this way, although it may contain unusual color artifacts.

All well and good, but not that detailed. It's noteworthy that it's off by default and it's certainly not a "if you want more DR, just check this box" box. If that was the case it would always be on.

I've had clips where the effect seemed like a pure win, and other clips that react closer to what the manual is describing.

I would like to learn more about this top area of the signal, that BMD ops to not include by default and what the inner workings/mappings are when the box is checked vs unchecked.

Info direct from BMD would be especially appreciated.

Since BM will probably not answer questions about this, I'll try an educated guess (educated by Red).

What others are doing to achieve something similar is copying the color channel which is least clipped into the other two for the highlight only. This will completely desaturate the highlight but can bring back some detail. Unfortunately, one needs some transition into the fully colored luminance values, and that's where the method can fail if you have strong saturation close to clipping. We have done this manually years ago with a luma mask and some channel ops, I assume it is just a one-click version of that. It works pretty well if you don't have much color in the highlight areas to bring back some definition, up to a half stop or two thirds if you are lucky.

My guess would be same as Uli’s, it does a clipped channel restoration by shuffling values from other channels.