+question, and the callback data (if any).
+
+The callback may not be called if you use GnuPG 2.x, which relies
+on the external program called `gpg-agent' for passphrase query.
+If you really want to intercept passphrase query, consider
+installing GnuPG 1.x _along with_ GnuPG 2.x, which does passphrase
+query by itself and Emacs can intercept them."