Key binding of a lambda function as a uninterned symbol,

key-bindings.el

(define-key ivy-mode-map (kbd "C-s")
  (defalias (make-symbol "swiper-or-swiper-all")
    ;; Wrapped in `defalias' with uninterned SYMBOL so `describe-key'
    ;; displays command as a proper symbol instead of byte-codes
    (lambda ()
      "Runs the command swiper.
With a prefix argument, run the command swiper-all."
      (interactive)
      (if current-prefix-arg
          (swiper-all)
        (swiper)))))