diff --git a/README.org b/README.org
index dbcc361..f8bd3f6 100644
--- a/README.org
+++ b/README.org
@@ -2036,6 +2036,27 @@ file.
 | *pdf-view-fit-width-to-window*  | {{{kbd(W)}}}   |
 |---------------------------------+----------------|
 
+** Reading outline files
+:PROPERTIES:
+:CUSTOM_ID: sec:reading-outline-files
+:END:
+
+#+caption[Enable ~read-only-mode~ for some files in ~outline-mode~]:
+#+caption: Enable ~read-only-mode~ for some files in ~outline-mode~.
+#+name: lst:maybe-read-only-in-outline-mode
+#+begin_src emacs-lisp -n :results silent
+(defun maybe-read-only-in-outline-mode ()
+  ;; GAV: Should be a toplevel function to call `message' here.
+  (let ((fnsd (buffer-file-name)))
+    ;; GAV: `fnsd' is nil during Org export to LaTeX.
+    (when fnsd
+      (setq fnsd (file-name-nondirectory fnsd))
+      (when (member fnsd '("NEWS" "ORG-NEWS" "PROBLEMS"))
+        (message "Visit `%s' in `read-only-mode'" fnsd)
+        (read-only-mode +1)))))
+(add-hook 'outline-mode-hook #'maybe-read-only-in-outline-mode)
+#+end_src
+
 * Writing
 :PROPERTIES:
 :CUSTOM_ID: sec:writing