What does '!' (exclamation mark) next to the file name represent in Xcode

I am wondering what does '!' (exclamation mark), next to the name of the file mean in Xcode. I know that it is meant to tell you that a file is "Missing", but I couldn't find any online explanation. And I also need a way to fix it. I can edit the code inside of the so-called "Missing" file. When I run it into the simulator everything works completely fine, no error and not even a warning.

Technical Data:

I am running Xcode 8 with Swift 3.

What I have tried so far:

• I tried re-opening Xcode --> didn't work
• I tried solving it with source-control --> nothing happened
• I searched for it inside my trash --> no file inside the trash with the same name
• I have checked the connections --> everything is fine

Images:

1. The file inside my editor:

Any help is greatly appreciated if it comes with a good explanation!

Since the "M" and "A" and "!" are referring to your repositories, I suspect that this file lives on your local drive but, for some reason, isn't found in wherever you are keeping your files remotely (GitHub, BitBucket, Subversion, etc.).

1)

If this were my problem, I'd look on your remote repository first to make sure the file exists there.

2)

Then I would also look at the path of the local file. Sure you can open it from your project/workspace, but perhaps it's in a different place/folder than all of the other source files.