From Halopedia, the Halo wiki
A Kindler is a small, floating, spherical device used by the Covenant when exploring unknown territory. The Kindler emits two oscillating beams of purple light that scan its surroundings as it moves, creating a holographic map for its handlers.
In late 2525, during the Battle of Alpha Corvi II, Covenant forces used a Kindler to explore the underground tunnels beneath the mining settlement of Black Reef in their search for Forerunner technology on the Human colony.
In 2551, during the Battle of Meridian, a Covenant Special Operations team used a Kindler to search for Forerunner artifacts hidden beneath the surface of the world. Ultimately, it discovered a Luminary inside a large Forerunner chamber.
The Kindler is very similar in design and function to the mapping drones used to scan LV-223's tunnels in the 2012 film Prometheus.
List of appearances