IIRC, it was a give-away after they changed Horizons from a stand-alone Season product (which included all ED base content), to a "DLC" style product, which still requires a separate purchase of the base ED game.
This was done to make life easier for Steam users, IIRC. Having Horizons as a separate product caused issues with some Steam data/stats/stuff.
It's an ideal paint job for using Mirrored Armor!