Variable: search-highlight
search-highlight is a customizable variable defined in isearch.el.gz.
Value
t
Documentation
Non-nil means incremental search highlights the current match.
Probably introduced at or before Emacs version 20.1.
Source Code
;; Defined in /usr/src/emacs/lisp/isearch.el.gz
;;; isearch highlight customization.
(defcustom search-highlight t
"Non-nil means incremental search highlights the current match."
:type 'boolean)