It is used for panel meters, totalizers and batch counters. The display is rendered as SVG, so it stays sharp at any size, and takes its colour from the theme. Unlit segments are drawn faintly, as on a real LED display.
A counter usually shows leading zeros; a measurement usually does not.
An empty value blanks the display. A value that does not fit in the configured number of digits lights the top bar of every digit, or the bottom bar when it is negative.
The height is set with a CSS variable. The colour follows the theme unless it is overridden.