Here is teardown of Stego FZK 011 thermostat. Thar is an electronechanical thermostat that can control heating resistor and/or cooling fan.
The thermostat is based on bimetal strip that bends based on temperature. To get sharp transition and some hysteresis there is also magnet near silver calibration adjustment screw and electrical contacts. Components on board are small 4700 pF capacitor for NC contact filtering and one resistor (marked as RF in circuit wiring).
The electrical NC contact (heater) is rated for 10A current at AC230V and NO contact (fan) for 5A. The contacts can also be used for low voltage signals (24V DC minimum 20 mA current for reliable indication).
RF had value of around 237 kohms. When wired at mains power application means about 1 mA current at 230V AC goes through the RF resistor when the heater is turned on. Around 230 mW power loss on resistor, which means some heating to bimetal strip to reduce hysteresis according to document that came with the product. According to manual the N contact connected to resistor can be left not connected if higher hysteresis is wanted than what is got when N is wired to neutrak.