It's the light for the auto start stop. The light means auto start stop is not functioning or not currently available. Some people would consider that a good thing, myself I don't mind auto start stop, if functioning correctly it's transparent.
If it doesn't work often, it is a sign that your battery isn't sufficiently charged. There was a recall on the 21-24 Sports, so we got a new AGM battery for free. If you look in the owner''s manual, it will explain the normal reasons the Auto/Stop/Start won't work.