Backport commit 2b5d43081 from Emacs

* lisp/ox.el (org-export-to-buffer): Modernize docstring accordingly.
* lisp/ox-latex.el (org-latex-export-as-latex):
* lisp/ox-koma-letter.el (org-koma-letter-export-as-latex):
* lisp/ox-beamer.el (org-beamer-export-as-latex):
Use `major-mode-remap` when available.

(major-mode-remap(-defaults)): New var and function (bug#69191)
2b5d43081a30f816dd38a16c7b5bfbad712a779b
Stefan Monnier
Sun Mar 3 23:58:18 2024 -0500

lisp/ox-beamer.el

@@ -1008,7 +1008,10 @@ will be displayed when `org-export-show-temporary-export-buffer'
 is non-nil."
   (interactive)
   (org-export-to-buffer 'beamer "*Org BEAMER Export*"
-    async subtreep visible-only body-only ext-plist (lambda () (LaTeX-mode))))
+    async subtreep visible-only body-only ext-plist
+    (if (fboundp 'major-mode-remap)
+        (major-mode-remap 'latex-mode)
+      #'LaTeX-mode)))
 
 ;;;###autoload
 (defun org-beamer-export-to-latex

lisp/ox-koma-letter.el

@@ -911,7 +911,9 @@ non-nil."
   (let (org-koma-letter-special-contents)
     (org-export-to-buffer 'koma-letter "*Org KOMA-LETTER Export*"
       async subtreep visible-only body-only ext-plist
-      (lambda () (LaTeX-mode)))))
+      (if (fboundp 'major-mode-remap)
+          (major-mode-remap 'latex-mode)
+        #'LaTeX-mode))))
 
 ;;;###autoload
 (defun org-koma-letter-export-to-latex

lisp/ox-latex.el

@@ -4160,7 +4160,10 @@ will be displayed when `org-export-show-temporary-export-buffer'
 is non-nil."
   (interactive)
   (org-export-to-buffer 'latex "*Org LATEX Export*"
-    async subtreep visible-only body-only ext-plist (lambda () (LaTeX-mode))))
+    async subtreep visible-only body-only ext-plist
+    (if (fboundp 'major-mode-remap)
+        (major-mode-remap 'latex-mode)
+      #'LaTeX-mode)))
 
 ;;;###autoload
 (defun org-latex-convert-region-to-latex ()

lisp/ox.el

@@ -6608,7 +6608,7 @@ use it to set a major mode there, e.g.,
     (interactive)
     (org-export-to-buffer \\='latex \"*Org LATEX Export*\"
       async subtreep visible-only body-only ext-plist
-      #\\='LaTeX-mode))
+      (major-mode-remap 'latex-mode)))
 
 When expressed as an anonymous function, using `lambda',
 POST-PROCESS needs to be quoted.