エラーメッセージってplistの中に入ってたんだね


(plist-put (symbol-plist 'quit) 'error-message "中断")
(plist-put (symbol-plist 'buffer-read-only) 'error-message "バッファは読み取り専用です")

(mapatoms (lambda (sym)
(let ((p (symbol-plist sym)))
(when (plist-member p 'error-conditions)
(insert (format "%s: %s - %s\n"
sym
(plist-get p 'error-conditions)
(plist-get p 'error-message)))))))