The Bondtech Heatlink JST MX-50-57-9002 is an adapter between thermistor or heater heatlink and the printer. The Heatlink is equipped with a standard Molex micro-fit 3.0 male connector and has a Molex type MX-50-57-9002 as a special connection.
You can find the corresponding Thermistor and Heater heatlink cables here: