Changes

The '''accessory_addon_data''' unit is used for vehicle accessories that add a visible component to a vehicle. This is most commonly used for customization of the [[Documentation/Engine/Game_data/Player_trucks_definitions|player's vehicle]]. It defines the paths to the visible models and their configuration (variant, look, excluded views), and the path to the collision mesh if applicable. Units of this type are typically found in '''/def/vehicle/truck/<make.model>/accessory/<type>/*.sii''', but some special accessories which don't directly interact with the player (eg badges which are dependent on the engine/chassis configuration) may also be found in '''def/vehicle/truck/<make.model>/<special_type>/*.sii'''.