It's just a small power-efficient lamp post with a built-in combinator for an easy color selection (opens on click).
Can be used for decoration, as a simple marker for specific places, circuit network signal indicator, or a single-slot constant combinator.
General glow parameters for these are configurable via mod options. There's also an option to add extra colors for all lamps to use.

Mod settings (startup tab):

• Add extra color signals

  Adds extra row of lamp color "virtual signals" to pick from, which can be used with regular lamps as well.
   

• Lamp Post glow radius

  Radius for lamp post glow, when any signal is set on it. Default: 6. 0 - disabled.
   

• Lamp Post glow intensity

  Glow intensity value for lamp posts, in 0 (no light) - 1.0 (bright) range. Default: 0.9.
   

• Lamp Post color intensity

  Lamp post glow color intensity, from 0 (white) to 1.0 (full color). Does not affect color of the lamp itself. Default: 0.135.
   

When pasing these lamps from blueprints, note that these will contain missing "Smart Lamp Data" items, which are settings for these lamps, and will be auto-created when lamp is built - no need to worry about those.