Maybe that’s a thing where you area at then. I’ve worked with heating units that have a simple temp probe and a manual dial that I converted to be “smart” by taking the outdoor temperature into account and then ramp the supply temperature up as the outdoor temp went down. This was a system that supplied hot water to radiators in an apartment building that was converted from a hotel. We replaced a pair of steam engine sized steam boilers to a direct fire hot water system by replacing the steam to water heat exchanger.

EVERY system I’ve worked on was the same, short the wires and it turns on. Anything beyond that is controlled by the heating unit. A simple thermostat just puts in the call by allowing the power to flow. When a system had multiple wires i.e. Heat and Cool plus fan you have 4 or more wires depending on the system capabilities. One supplies power or ground the others control fan, heat, or cool by being shorted to the power or ground wire. Sometimes there are multiple stages that are controlled by the thermostat sometimes they are controlled by the HVAC units built in controller. But MILLIONS of homes and businesses in the US work in a similar fashion and even without a thermostat installed a tech can short the needed wires and make them work.

https://home.howstuffworks.com/home-thermostat.htm