Are those sources target independent or specific for each new build of the package? That is, is there a new source code package on hydra when one of the depende

Are those sources target independent or specific for each new build of the package? That is, is there a new source code package on hydra when one of the dependencies changes? Or does it only change if the package itself changes? Fixed-output derivations are used for sources (they are content-addressed in the store), so the latter.