Variable: whitespace-big-indent-regexp
whitespace-big-indent-regexp is a customizable variable defined in
whitespace.el.gz.
Value
"^\\(\\(?: \\{4,\\}\\| \\{32,\\}\\)[ ]*\\)"
Documentation
Specify big indentation regexp.
If you're using mule package, there may be other characters
besides "\\t" that should be considered TAB.
NOTE: Enclose always by \\( and \\) the elements to highlight.
Use exactly one pair of enclosing \\( and \\).
Used when whitespace-style includes big-indent.
This variable was added, or its default value changed, in Emacs 25.1.
Probably introduced at or before Emacs version 25.1.
Source Code
;; Defined in /usr/src/emacs/lisp/whitespace.el.gz
(defcustom whitespace-big-indent-regexp
"^\\(\\(?:\t\\{4,\\}\\| \\{32,\\}\\)[\t ]*\\)"
"Specify big indentation regexp.
If you're using `mule' package, there may be other characters
besides \"\\t\" that should be considered TAB.
NOTE: Enclose always by \\\\( and \\\\) the elements to highlight.
Use exactly one pair of enclosing \\\\( and \\\\).
Used when `whitespace-style' includes `big-indent'."
:version "25.1"
:type '(regexp :tag "Detect too much indentation at the beginning of a line")
:group 'whitespace)