During my Ph.D. work at a university, I followed up on someone else's doctoral work (I am no longer associated with that university). This person provided me with the source code for his work. I subsequently discovered that this source code is a slightly modified copy of some publicly available sources, which have a GPL license. The modifications are mostly some instruction toggling/rebracketing and variable renaming. Just a few instructions contain slight modifications (that I personally do not find any more justifiable than the variable renaming). Moreover, in the versions that this person gave me, the authorship headers of the original authors are replaced by his own and the copyright mentions of the university in question are also added. The GPL license notice, that is present in the original sources, is removed from all but one package.
I had reported these observations to my supervisors (who also supervised the work of the person in question), but they sought to suppress the matter and warned me of legal actions if I reported this matter any further (hence I am not reporting it directly to the university, which by the way does not seem to have an ethics committee). I'll note that these observations in the source code are part of several issues that I observed in this person's work (that involves several publications and his doctoral dissertation; I'll probably ask for advice regarding that in separate questions).
Is it legally safe if I publicly share the source code provided by this person along with the links to the online available original sources? The code was transferred to me by this person through a sharing link that is no longer available. I can only prove that I reported my observations to my supervisors as well as to this person (he responded by reaffirming that the source code was developed at the university in question and refused any further communication). I'll note that an engineer at the university trans-coded some of the source code in question for use in a commercial product for which the university had a collaboration with a private firm.