IIRC, the file names are in the format "CAR_name.eng". When you open the sound editor, you do not see the "CAR" tag, you only see the name. I would guess that your file is named like this.... "XFG_FBM_001.eng".
Default file would be "XFG_Default.eng" and you would only see "Default" in the editor. Your file is "XFG_FBM_001.eng" as I've said and is only displaying the name "FBM_001" in the editor.
Where you get the default thoughts I don't understand because your screenshot doesn't say "default" at all.