Variable: dired-omit-case-fold
dired-omit-case-fold is a customizable variable defined in
dired-x.el.gz.
Value
filesystem
Documentation
Determine whether "omitting" patterns are case-sensitive.
When nil, always be case-sensitive; when t, always be
case-insensitive; the default value, filesystem, causes case
folding to be used on case-insensitive filesystems only.
This variable was added, or its default value changed, in Emacs 26.1.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/dired-x.el.gz
(defcustom dired-omit-case-fold 'filesystem
"Determine whether \"omitting\" patterns are case-sensitive.
When nil, always be case-sensitive; when t, always be
case-insensitive; the default value, `filesystem', causes case
folding to be used on case-insensitive filesystems only."
:type '(choice (const :tag "Always case-sensitive" nil)
(const :tag "Always case-insensitive" t)
(const :tag "According to filesystem" filesystem))
:group 'dired-x
:version "26.1")