Variable: register-preview-function
register-preview-function is a variable defined in register.el.gz.
Value
register-preview-default
Documentation
Function to format a register for previewing.
Called with one argument, a cons (NAME . CONTENTS), as found
in register-alist. The function should return a string, the
description of the argument.
Source Code
;; Defined in /usr/src/emacs/lisp/register.el.gz
(defvar register-preview-function #'register-preview-default
"Function to format a register for previewing.
Called with one argument, a cons (NAME . CONTENTS), as found
in `register-alist'. The function should return a string, the
description of the argument.")