gnus-undo-mode
gnus-undo-mode is an interactive autoloaded compiled Lisp function in `gnus-undo.el
'.
(gnus-undo-mode &optional ARG)
Minor mode for providing `undo' in Gnus buffers.
key binding
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C-x Prefix Command
ESC Prefix Command
C-_ gnus-undo
C-/ gnus-undo
C-x u gnus-undo
C-M-_ gnus-undo