I have been hosting with Scala Hosting for awhile and they have a feature that locks down WordPress files, as best I can tell they are using the chattr command to make files immutable. It is obvious that they are very selective with the process because I never have issues with WordFence and other plugins that require the ability to write to their own files.
Does anyone have a list or suggestions on files that can safely be made immutable? Or the opposite, those that cannot be made immutable?