NaturesAura/src/main/resources/data/naturesaura/advancements/end_flower.json

{
    "display": {
        "icon": {
            "item": "naturesaura:end_flower"
        },
        "title": {
            "translate": "advancement.naturesaura.end_flower"
        },
        "description": {
            "translate": "advancement.naturesaura.end_flower.desc"
        }
    },
    "parent": "naturesaura:wood_stand",
    "criteria": {
        "killed_dragon": {
            "trigger": "minecraft:player_killed_entity",
            "conditions": {
                "entity": {
                    "type": "ender_dragon"
                }
            }
        }
    }
}