feedmail-prompt-before-queue-help-supplement

feedmail-prompt-before-queue-help-supplement is a variable defined in `feedmail.el'.
Its value is

nil

Documentation:
User-provided supplementary help string for the message action prompt.
When the message action prompt is shown, the user can as for verbose help,
at which point a buffer pops up describing the meaning of possible
responses to the prompt. Through various customizations (see, for
example, `feedmail-prompt-before-queue-user-alist'), the available responses
and the prompt itself can be changed. If this variable is set to a string
value, that string is written to the help buffer after the standard info.
It may contain embedded line breaks. It will be printed via `princ'.

You can customize this variable.