I ran file --mime-type "file.csv" in the terminal on macOS (Monterey Version 12.4) and received file.csv: text/plain. After modifying re-saving the file, I received file.csv: text/csv with the same command.

Ran the app on iOS 15.4. Viewed the returned file on macOS. If I open and re-save the file using a text editor, the MIME type changes. I need the app to return the correct MIME type.