Patch for reftex.el: master or release branch?

[Arash Esbati <arash@gnu.org>]

Dear maintainers,

I have the following patch for reftex.el fixing AUCTeX bug#59638.  This
issue was introduced with commit 1e8bb313ea:

--8<---------------cut here---------------start------------->8---
diff --git a/lisp/textmodes/reftex.el b/lisp/textmodes/reftex.el
index f815419ea4..126b3777f5 100644
--- a/lisp/textmodes/reftex.el
+++ b/lisp/textmodes/reftex.el
@@ -1004,10 +1004,13 @@ reftex-compile-variables
                   reftex-section-levels))

     ;; Calculate the regular expressions
-    (let* (
-;          (wbol "\\(\\`\\|[\n\r]\\)[ \t]*")
-           (wbol "\\(^\\)%?[ \t]*") ; Need to keep the empty group because
-                                    ; match numbers are hard coded
+    (let* (;; (wbol "\\(\\`\\|[\n\r]\\)[ \t]*")
+           ;; Need to keep the empty group because match numbers are
+           ;; hard coded
+           (wbol (concat "\\(^\\)"
+                         (when (string-suffix-p ".dtx" (buffer-file-name) t)
+                           "%")
+                         "[ \t]*"))
            (label-re (concat "\\(?:"
                             (mapconcat #'identity reftex-label-regexps "\\|")
                             "\\)"))
--8<---------------cut here---------------end--------------->8---

Can you please tell me if this should go to master or emacs-29 branch?

TIA.  Best, Arash