TanCurve component

Hello everyone! It's my first post here and it's a question. I searched but found no direct answer.

I tried making curves using points and tangent vectors corresponding to each point. Everything works fine apart from the blend curve parameter. Could you please explain how it works? I could experimentally find proper values, but I don't really understand how it functions. It looks like it is related to handles, but in this case why is there only one vector and only one blend value for each point?