Highlight Alert
A playback warning, often called blinkies, that flashes any area of the image where the brightest tones have clipped.
In depth
Highlight alert is calculated from the JPEG preview, not the raw data, so it is conservative — some blinking areas still hold recoverable detail in the raw file, typically a third to a full stop. Setting a neutral or flat picture profile makes the warning more honest by keeping the preview closer to the raw response.
Examples in practice
A landscape shows blinkies across the sun's immediate halo but not the clouds, confirming the exposure is safe.