in the description you wrote

When placed, connectors will attempt to determine whether they should act in input mode or output mode by looking at the connected building. This works for vanilla boilers/heat exchangers, steam engines/turbines, ...

the steam output of boilers and heat exchangers is only an output and thus can be automatically detected. but what about the water connections of them, and what about the steam connections of steam engines and turbines? all of those can act as input or output when chaining the steam engines and turbines. can they really also be detected automatically ?

examples:
pump -> boiler(water) <-> boiler(water) <-> boiler(water) <-> buffertank
boiler(steam) -> engine <-> engine <-> engine <-> buffertank
the pump and boiler(steam) should be detectable, the buffertanks are documented to not be detectable, but what about the direction between the chained entities ?

Boiler/heat exchanger water connections and steam engine/turbine connections are assumed to be inputs, since the most common configuration is a chained series that consumes all the water or steam available. You can of course use the key combination to change mode if you are using an unusual layout.