Item_BucketOfAquaticMob: {
    type: "compound";
    value: {
        tag?: {
            type: "compound";
            value: {
                AppendCustomName: { type: "byte"; value: number };
                BodyID?: { type: "string"; value: string };
                Color2ID?: { type: "string"; value: string };
                ColorID?: { type: "string"; value: string };
                CustomName?: { type: "string"; value: string };
                GroupName?: { type: "string"; value: string };
            };
        } & ActorPrefix;
    };
} & Item_ItemStack

Additional fields for bucket.