minibuffer-eldef-shorten-default

minibuffer-eldef-shorten-default is a variable defined in `minibuf-eldef.el'.
Its value is

nil

Documentation:
If non-nil, shorten "(default ...)" to "[...]" in minibuffer prompts.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.