Within X Rebirth, player-created content that changes the way the game works is called "extensions" and those that are in-use can be seen listed in-game via the main menu. Extensions are equivalent to within earlier Egosoft games, where player-created content took the form or "scripts" or "mods". Given that past familiarity, X Rebirth extensions are sometimes called mods and their creators are still refereed to as modders.
Please note that the use of extensions or save game edits can break games either of themselves, after future game updates, or via conflict with other extensions. Consequently, Egosoft are not generally able to support such modified games (see here for further details). However, do feel free to post any problems you may experience in appropriate threads on the X Rebirth - Scripts and Modding forum as the creator or others may be able to help you.
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