message-signature

message-signature is a variable defined in `message.el'.
Its value is

t

Documentation:
*String to be inserted at the end of the message buffer.
If t, the `message-signature-file' file will be inserted instead.
If a function, the result from the function will be used instead.
If a form, the result from the form will be used instead.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 23.2 of Emacs.