Combustion models defined without a transport package
 

Some combustion models (diffusion, FSD, infinitelyFastChemistry) require the definition of a transport package (constTransport, sutherlandTransport) while others (noCombustion, laminar, PaSR) don't.

Why is it like that? In which aspect the second group of combustion models differs from the first one, so to not need the definition of a transport package?