Tweak the `which-function-mode' section

README.org

@@ -4745,10 +4745,11 @@ it for this buffer is by typing {{{kbd(C-c C-e t U)}}} to export the it to a
 :CUSTOM_ID: sec:which-function-mode
 :END:
 
-The post [[https://codelearn.me/2024/02/02/emacs-which-function-mode.html][Emacs: which-function-mode]] claims that ~which-function-mode~ works in
+Listing [[lst:setup-which-function-mode]] sets ~which-function-mode~ options.  The
+post [[https://codelearn.me/2024/02/02/emacs-which-function-mode.html][Emacs: which-function-mode]] claims that ~which-function-mode~ works in
 ~org-mode~.  This is true in case all document headlines are simple, but is not
 true in case document headlines contain links.  The code in listing
-[[lst:setup-which-function-mode]] has stolen ideas from the following links:
+[[lst:define-for-which-func-functions]] has stolen ideas from the following links:
 - [[https://list.orgmode.org/20240205.141235.268481480563517065.teika@gmx.com/][Show current org-mode headline in frame header]].
 - [[https://emacs.stackexchange.com/questions/30894/][Show current org-mode headline in modeline]].
 
@@ -4756,8 +4757,21 @@ true in case document headlines contain links.  The code in listing
 #+caption: Setup ~which-function-mode~.
 #+name: lst:setup-which-function-mode
 #+begin_src emacs-lisp -n :results silent
-;; https://emacs.stackexchange.com/questions/30894/
+(setopt which-func-modes '(emacs-lisp-mode org-mode pdf-view-mode))
+
+;; It looks like `python-mode' does nothing when they it is an element
+;; of `which-func-modes'.
+
+;; (setopt which-func-modes t)
+
 ;; (setopt which-func-display 'header) ;; AFAIU, fails on my system.
+#+end_src
+
+#+caption[Define functions for ~which-func-functions~]:
+#+caption: Define functions for ~which-func-functions~.
+#+name: lst:define-for-which-func-functions
+#+begin_src emacs-lisp -n :results silent
+;; https://emacs.stackexchange.com/questions/30894/
 (defvar which-func-functions nil)
 
 (defun which-func-org-function ()