Mengapa defvar scoping bekerja secara berbeda tanpa initvalue?

Misalkan saya memiliki file bernama elisp-defvar-test.elmengandung: ;;; elisp-defvar-test.el --- -*- lexical-binding: t -*- (defvar my-dynamic-var) (defun f1 (x) "Should return X." (let ((my-dynamic-var x)) (f2))) (defun f2 () "Returns the current value of `my-dynamic-var'."...