I want to alter a HTTP header and I am looking for the appropriate hook to use. I can tell a general time of when some hooks are called but not exactly when. How do I know exactly when hooks are called, and what hook I should be using to change my header?
edit: I have managed to change my HTTP header. But something else is adding to my header and that is taking precedent over my header portion. Is there a way to know where this is coming from?