CTRL A to select all, right click, Edit, Revert or Revert to Original. Might need to do it a few times and sort into different categories, like built in = true plus faulty = true first, those should all revert to original. Faulty = true plus built in = false some will, some won't. And be advised for some older content that won't work, it's faulty because it's faulty, not because it's been modified, if the original version is faulty then reverting to original won't suddenly make it not faulty.
