Clean up the implementation of the org-mode kbd macro

README.org

@@ -885,7 +885,7 @@ in listing [[lst:configure-tex]] corrects this by advising to override
 :END:
 
 The code in listing [[lst:customize-org-babel]], [[lst:customize-org]], and
-[[lst:customize-org-export]] does basic customization of [[https://orgmode.org/][Org Mode]] variables.
+[[lst:customize-org-export]] does basic customization of [[https://orgmode.org/][Org mode]] variables.
 
 #+caption[Customize =org-babel=]:
 #+caption: Customize =org-babel=.
@@ -987,7 +987,7 @@ The code in listing [[lst:customize-org-babel]], [[lst:customize-org]], and
                                 (diff "diff")
                                 (shell-script "bash")
                                 (caml "ocaml")
-                                (org "latex")))
+                                (org "text")))
      '(org-latex-minted-options '(("bgcolor" "LightGoldenrodYellow")))
      `(org-latex-logfiles-extensions
        ',(cl-union '("lof" "lot") org-latex-logfiles-extensions :test #'equal))
@@ -1311,7 +1311,7 @@ Evaluation of the source block in listing
 [[lst:make-source-block-with-export-keyword-settings]] produces the source block
 that exports to listing [[lst:source-file-export-keyword-settings]] which shows the
 first six lines of this [[file:README.org]] file.  The last two lines show that
-[[file:setup-include.org][setup-include.org]] is argument for [[info:org#Export Settings][#+SETUPFILE:]] *and* [[info:org#Export Settings][#+INCLUDE:]].
+[[file:setup-include.org][setup-include.org]] is the argument for [[info:org#Export Settings][#+SETUPFILE:]] *and* [[info:org#Export Settings][#+INCLUDE:]].
 
 #+caption[Make setup and include file export keyword settings source block]:
 #+caption: The shell script to make the source block containing the export
@@ -1343,21 +1343,41 @@ first six lines of this [[file:README.org]] file.  The last two lines show that
 #+end_src
 :end:
 
-Listing [[lst:setup-include-export-keyword-settings]], [[lst:use-latex-header-1]],
+Listing [[lst:setup-include-export-keyword-settings]] tangles into the
-[[lst:use-latex-header-2]], [[lst:use-latex-header-3]], and [[lst:use-latex-header-4]]
+[[file:setup-include.org][setup-include.org]] file and listing [[lst:by-backend-kbd-org-macro]] defines
-tangle into the [[file:setup-include.org][setup-include.org]] file.
+the tools for the [[https://orgmode.org/][Org mode]] =kbd= macro in [[file:setup-include.org][setup-include.org]].
 
 #+caption[Setup and include file export keyword settings]:
 #+caption: Setup and include file export keyword settings.
 #+name: lst:setup-include-export-keyword-settings
 #+begin_src org
   ,#+babel: :cache no
-  ,#+macro: kbd (eval (by-backend (html (format "@@html:<kbd>%s</kbd>@@" (htmlize-protect-string $1))) (latex (format "@@latex:\\colorbox{PowderBlue}{\\texttt{%s}}@@" $1))))
+  ,#+macro: kbd (eval (by-backend-kbd-org-macro $1))
   ,#+property: header-args:emacs-lisp :exports code :results silent :tangle init.el
   ,#+property: header-args:org :tangle setup-include.org
   ,#+startup: content
 #+end_src
 
+#+caption[Define the tools of the org-mode =kbd= macro]:
+#+caption: Define the tools for the org-mode =kbd= macro.
+#+name: lst:by-backend-kbd-org-macro
+#+begin_src emacs-lisp
+  (with-eval-after-load 'ox
+    (autoload 'htmlize-protect-string "htmlize" nil t)
+
+    (defmacro by-backend (&rest body)
+      `(cl-case org-export-current-backend ,@body))
+
+    (defun by-backend-kbd-org-macro (keys)
+      (by-backend
+       (html (format "@@html:<kbd>%s</kbd>@@" (htmlize-protect-string keys)))
+       (latex (format "@@latex:\\colorbox{PowderBlue}{\\texttt{%s}}@@" keys)))))
+#+end_src
+
+Listing [[lst:use-latex-header-1]], [[lst:use-latex-header-2]], [[lst:use-latex-header-3]],
+and [[lst:use-latex-header-4]] tangle into the [[file:setup-include.org][setup-include.org]] file in order to
+create the [[https://www.latex-project.org/][LaTeX]] preamble.
+
 #+caption[LaTeX preamble: language, lists and floats]:
 #+caption: LaTeX preamble: language, lists and floats.
 #+name: lst:use-latex-header-1
@@ -1610,25 +1630,15 @@ Listing [[lst:emacs-lisp-setup-call]] initializes the buffer local variables
   ,#+end_src
 #+end_src
 
-#+caption[Specify export backend dependent header arguments]:
-#+caption: Specify export backend dependent header arguments.
-#+name: lst:header-arguments-by-backend
-#+begin_src emacs-lisp
-  (with-eval-after-load 'ox
-    (defmacro by-backend (&rest body)
-      `(cl-case org-export-current-backend ,@body)))
-#+end_src
-
 This section updates the outdated [[https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-LaTeX.html#orgcc214c1][Worg: backend dependent execution]] example to
 Emacs-27.2 and Org-9.5.2.  It shows how to export [[https://en.wikipedia.org/wiki/PGF/TikZ][PGF/TikZ]] images to:
 1. [[https://en.wikipedia.org/wiki/PDF][PDF]] by embedding in [[https://www.latex-project.org/][LaTeX]].
 2. [[https://en.wikipedia.org/wiki/HTML][HTML]] by passing from [[https://www.latex-project.org/][LaTeX]] by [[https://en.wikipedia.org/wiki/PDF][PDF]] and to [[https://en.wikipedia.org/wiki/Scalable_Vector_Graphics][SVG]].
 Listing [[lst:backend-dependent-execution-update]] tangles to
 [[file:worg-backend-dependent-execution-update.org][worg-backend-dependent-execution-update.org]] as either a standalone example or an
-example for inclusion. Listing [[lst:header-arguments-by-backend]] tangles to the
+example for inclusion.  Finally, inclusion of
-=user-init-file= to make the convenience =by-backend= macro always available.
+[[file:worg-backend-dependent-execution-update.org][worg-backend-dependent-execution-update.org]] produces here the figure with the
-Finally, inclusion of [[file:worg-backend-dependent-execution-update.org][worg-backend-dependent-execution-update.org]] produces here
+nodes 1, 2, 3, and 4:\\
-the figure with the nodes 1, 2, 3, and 4:\\
 #+include: worg-backend-dependent-execution-update.org
 How to include such figures as floats remains an open question.