A plug-in is a mod that adds a feature(s) to the already existing sandbox map provided by simple planes. For example, the ocean mod or clouds mod. A mod-mod is a mod that can add parts or systems to the game and/or add a separate map to the game apart from the map provided by the game. These maps will appear in the menu. An example of this are the stork island, simple_land, and the Kumamatanga Archipelago map.
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A plug-in is a mod that adds a feature(s) to the already existing sandbox map provided by simple planes. For example, the ocean mod or clouds mod. A mod-mod is a mod that can add parts or systems to the game and/or add a separate map to the game apart from the map provided by the game. These maps will appear in the menu. An example of this are the stork island, simple_land, and the Kumamatanga Archipelago map.