Variable: button-buffer-map
button-buffer-map is a variable defined in button.el.gz.
Value
<backtab> backward-button
C-M-i backward-button
TAB forward-button
Documentation
Keymap useful for buffers containing buttons.
Mode-specific keymaps may want to use this as their parent keymap.
Probably introduced at or before Emacs version 28.1.
Source Code
;; Defined in /usr/src/emacs/lisp/button.el.gz
(defvar-keymap button-buffer-map
:doc "Keymap useful for buffers containing buttons.
Mode-specific keymaps may want to use this as their parent keymap."
"TAB" #'forward-button
"ESC TAB" #'backward-button
"<backtab>" #'backward-button)