Cura/resources/extruders/geeetech_A10T_3.def.json

{
    "version": 2,
    "name": "Extruder 3",
    "inherits": "fdmextruder",
    "metadata": {
        "machine": "geeetech_A10T",
        "position": "2"
    },

    "overrides": {
        "extruder_nr": {
            "default_value": 2,
            "maximum_value": "2"
        },
        "machine_nozzle_size": { "default_value": 0.4 },
        "material_diameter": { "default_value": 1.75 }

    }
}