Following on from the free weekend a couple of weeks ago, Endless Space 2 adds the free Renegade Fleets update today, with 6 new skins, AI Modding, and a Hissho comic, as a result of the playerbase logging in more than a million hours during the free weekend (in fact, 2.8 million hours was played).
If you're interested in Endless Space 2 it's currently 66% off over on Steam.