Yeah, I'm with SteveF, those could be brake rivets. If they are, they have no business within a tire. The maintainer who allowed that error to occur should explain themselves....
Your more clear photo will be welcome, and may cause a refinement of thoughts. That is not wear and tear, that's faulty maintenance. You're within your rights to file a service difficulty report with the FAA. Keep the bits in case they would like to look.