> Since you are changing the function signatures anyway,
> you could make them consistent between `dired-map-over-marks'
> and `dired-get-marked-files' by adding an explicit arg `marker-char',
> i.e. both `dired-get-marked-files' and `dired-map-over-marks'
> could end with "distinguish-one-marked marker-char all-marks",
> thus explicitly passing `marker-char' arg down the call chain.
> Then you'll need `(or marker-char dired-marker-char)' in
> `dired-marker-regexp' for backward-compatibility.  And then also
> no need to let-bind `dired-marker-char' in `dired-get-marked-files'
> (it's better to avoid dynamically binding global variables where possible).

It sounds good. Thank you. Implemented in the new patch.