Warning: you can not change read only file
I expected to be able to save my changes.
I got a warning strip at the top of the editor panel:
"Warning: You are changing a read-only file." with a "Make writable" button.
I cannot make it writable and cannot save the changes without renaming the file.
Try opening it with a text editor, then save (with the same name - overwrite), making sure it is set to UTF-8 encoding and (optionally) Unix line endings.