Alternative Factorio, slightly changed rules/recipes and cosmetic changes, a bit more scientifically oriented "Warehouse", substations have a large supply area, more use for wood, charcoal recipe, sulfur gained from crude oil and coal instead of gas. Less spoiling items, more resources from asteroids. Look carefully at the recipes. Optional, more beautiful day-night-cycles on planets. In principle not a golden release, especially for the icons.
Mods introducing new content into the game.