This data structure contains all of the information needed to resolve a filename format string from the Movie Graph. During runtime the values are generated by the actual rendering and then placed into this data structure before resolving an actual {format_string} using theUMovieGraphBlueprintLibrary. You can use this to resolve filenames when editing. If you wish to resolve a partial format string (such as {sequence_name}/{frame_number} but have it only resolve {sequence_name} you can add ("frame_number", "{frame_number}") to the FileNameFormatOverrides and that portion of the format string will be preserved so the resulting string back would say "my_seq_name/{frame_number}".