bogert wrote:
Thanks. It's a bit weird, but if I doesn't hurt performance or take up an inordinate amount of disk space I am inclined to leave it alone as you suggest.
First of all, this is a system folder. You should not be in that folder at all. You should definitely leave it alone. There is no change you can make in that folder that would not lead to catastrophic damage and data loss.
The macOS operating system is the most complicated operating system ever made. Every year, it gets worse. I have seen numerous cases where people try to dig into the internals to figure out what is going on and quite literally lost touch with reality. I am not exaggerating.
Apple, of course, knows how complicate all of this is. They have made the Finder and other graphical user interfaces so that they display a very simplified view of this complex file system, to avoid confusing people. That is what you are seeing here. But when you try to use the Finder to view a system folder like this, you risk even greater confusion because the Finder isn't supposed to be used on these system folders at all.
In fact, there are no duplicates in this folder. The Finder has the ability to display alternate names for files and folders. For example, the actual name of the "Preview" app is "Preview.app". You don't see the ".app" part because it is hidden by default. If you had your system configured to use a French user interface, it would show up as "Aperçu" instead. There is metadata inside these special folders (called "bundles") that controls the "human version" of the name. In most cases, Anglophones are privileged because Apple developers are Anglophones and they more or less see files the way they really are. This is a case where you see the file system like the rest of the world does - faked out. You could explore this folder using the Terminal (please see my note above about catastrophic damage and data loss - that goes double for the Terminal). But if you are careful, then you would see all of the real file names.