never mind... the current version (5.8) of the response has that info: "charger_phases":3
here is the response of my car:
{ "charging_state":"Charging",
"charge_limit_soc":90, "charge_limit_soc_std":90, "charge_limit_soc_min":50, "charge_limit_soc_max":100, "charge_to_max_range":false, "battery_heater_on":false, "not_enough_power_to_heat":false, "max_range_charge_counter":0, "fast_charger_present":false, "battery_range":184.47, "est_battery_range":87.06, "ideal_battery_range":147.58, "battery_level":66, "battery_current":27.6, "charge_energy_added":10.7, "charge_miles_added_rated":41.5, "charge_miles_added_ideal":33.0, "charger_voltage":232, "charger_pilot_current":16, "charger_actual_current":16, "charger_power":4, "time_to_full_charge":2.03, "charge_rate":31.1, "charge_port_door_open":true, "scheduled_charging_start_time":null, "scheduled_charging_pending":false, "user_charge_enable_request":null, "charge_enable_request":true, "eu_vehicle":true, "charger_phases":3 }
