Cura/resources/extruders/builder_premium_large_rear.def.json

{
    "id": "builder_premium_large_rear",
    "version": 2,
    "name": "Rear Extruder",
    "inherits": "fdmextruder",
    "metadata": {
        "machine": "builder_premium_large",
        "position": "0"
    },

    "overrides": {
        "extruder_nr": {
            "default_value": 0,
            "maximum_value": "1"
        },
        "machine_nozzle_offset_x": { "default_value": 0.0 },
        "machine_nozzle_offset_y": { "default_value": 0.0 },

        "machine_extruder_start_pos_abs": { "default_value": true },
        "machine_extruder_start_pos_x": { "value": "prime_tower_position_x" },
        "machine_extruder_start_pos_y": { "value": "prime_tower_position_y" },
	    "machine_extruder_end_pos_abs": { "default_value": true },
        "machine_extruder_end_pos_x": { "value": "prime_tower_position_x" },
        "machine_extruder_end_pos_y": { "value": "prime_tower_position_y" },
		"extruder_prime_pos_abs": { "default_value": true }
    }
}