Emacs: Highlight Brackets
- Alt+x
show-paren-mode
- highlight matching brackets when your cursor is on a bracket.
In emacs init file, use
(show-paren-mode 1)

show-paren-mode has 2 styles of highlighting brackets. By default, emacs highlights just the brackets.
To change a style, put one of this in your emacs init file:
;; highlight brackets (setq show-paren-style 'parenthesis)
;; highlight entire expression (setq show-paren-style 'expression)
;; highlight brackets if visible, else entire expression (setq show-paren-style 'mixed)
Note: show-paren-mode
will highlight any brackets, including [] {} 『』 【】 〈〉 «» etc. [see Unicode: Brackets, Quotes «»「」【】《》]