question: public static void registerHorseArmor ( ResourceLocation id , HorseArmorType type ) { AutomaticNamespacedRegistry < ResourceLocation , HorseArmorType > registry = Registries . get ( HorseArmorType . class ) ; if ( type == null ) { throw new NullPointerException ( "Attempted to register a null horse armor" ) ; } else if ( id == null ) { throw new NullPointerException ( "Attempted to register a horse armor with a null ID" ) ; } else if ( registry . containsKey ( id ) ) { throw new IllegalArgumentException ( String . format ( "The horse armor ID \"%s\" has already been registered" , id ) ) ; } registry . register ( id , type ) ; }
target:  Registers a horse armor.