(defstruct s-1
  k)

(defmethod (setf set-s-k) (new (f s-1))
  (setf (foo-k f) new))

Could you tell me:

(1) What is the name of the GF this method defined on?

(2) How to write this method in the style
    (defgeneric foo (a b)
      (:method
      ;; .......
      ))

(2) How I can find this method e.g (FIND-METHOD ...

Also I'd like to know how to remove it but this is probably will be
obvious where I'll know answers to the Q above.

Closely related question is about SETF functions(e.g (DEFUN (SETF FOO)
...). Plain function could be introduced with DEFUN and could be
FMAKUNBOUNDed. What syntax for actions similar to FMAKUNBOUND used for
SETF functions ?

  (setf set-s-k)

  Look up "function name" in the glossary.

  (find-method #'(setf set-s-k) '() (list (find-class s-1)))

but I've forgotten the built in class T. in the list of
specializers.This misled me and I decided (wrongly) that I use wrong
syntax for that.

Nevertheless I've learn subject better.