The clipping indicators in Lightroom show when a channel or all channels are clipping in either the shadows or the highlights, but I've seen them used in two ways:
Use them as an indicator of when you have a pure white / black so that for a full tonal range both shadow and highlight clipping indicators will be showing (although perhaps only a tiny number of pixels will actually be clipped.
Use them as an indicator of when you have gone too far, so when a clipping indicator shows, the user backs off slightly, so for a full tonal range the white and black points will be just short of triggering the clipping indicators.
So which is correct? Do they indicate a value has been pushed beyond maximum (or minimum) or that a value is at maximum or minimum?
Note: This isn't a question about what clipping is or whether in some circumstances clipping is OK. All I want to know is exactly what the meaning of the clipping indicators are in Lightroom. Do they mean at or over.