emacs-save-session-functions

emacs-save-session-functions is a variable defined in `x-win.el'.
Its value is

nil

• This variable may be risky if used as a file-local variable.

Documentation:
Special hook run when a save-session event occurs.
The functions do not get any argument.
Functions can return non-nil to inform the session manager that the
window system shutdown should be aborted.

See also `emacs-session-save'.