Constant ENTITY_AUTOMATION 

pub const ENTITY_AUTOMATION: EntityCapabilityKey<dyn ResourceHandler<ItemResource>, Option<Direction>>;

An entity’s items as automation reaches them, as NeoForge 26.3’s Capabilities.Item.ENTITY_AUTOMATION, asked for the side of the entity a hopper reaches it from. The game answers it for a chest or hopper minecart and a chest boat, the container entities EntitySelector.CONTAINER_ENTITY_SELECTOR picks, with the slots ENTITY_ITEMS gives them; a player and a chested mount are not reached by automation.