What Does Question Mark Mean in Xcode Project Navigator?
You can add to source control by selecting the untracked files
Those characters refer to the source control.
- ? - Unversioned
- M - Modified
- A - Added
- A+ - Moved/Renamed (R as of Xcode 13)
- U - Newer version of a file on source control
More reference here
It's the file untracked by source control.