When dired-x.el is loaded, some standard Dired functions from
dired.el and dired-aux.el offer additional features.
dired-add-entry obeys Dired Omit mode (see Omitting Files in Dired), if it is active.
dired-initial-position respect the value of
dired-find-subdir (see Miscellaneous Commands).
dired-clean-up-after-deletion respects the value of
dired-guess-shell-command (see Shell Command Guessing) to
offer a smarter default command.