Re: info inconsistency about "Shell Commands in Dired"

[Richard Stallman]

    For a command to be used with dired-do-shell-command, M-? inserts
    a special marker -- e.g. a `?' character with a dedicated text
    property, e.g. '(expand t).  Then dired-do-shell-command shall look
    for characters with that property and do the replacement on those.

This would be ok as long as we don't assign any other meaning to M-?
that is useful inside all minibuffers.