ediff-brief-help-message-function is a variable defined in `ediff-help.el'.
Its value is

  • Automatically becomes permanently buffer-local when set.
  • This variable may be risky if used as a file-local variable.

The brief help message that the user can customize.
If the user sets this to a parameter-less function, Ediff will use it to
produce the brief help message. This function must return a string.