Get rid off the Maxima section and clean up

README.org

@@ -2386,7 +2386,6 @@ list detailing and motivating each listing:
      (lilypond . ,(fboundp 'lilypond-mode))
      (lisp . t)
      (lua . ,(fboundp 'lua-mode))
-     (maxima . t)
      (org . t)
      (perl . t)
      ;; Beware of circular Python dependencies.
@@ -2472,10 +2471,6 @@ list detailing and motivating each listing:
   (defun org-babel-execute:toml (_body _params)
     "NO-OP to silence warnings." nil)
 
-  ;; Modes are not installed:
-  (defun org-babel-execute:maxima (_body _params)
-    "NO-OP to silence warnings." t)
-
   ;; Sections not exported:
   (defun org-babel-execute:applescript (_body _params)
     "NO-OP to silence warnings." nil)
@@ -3276,7 +3271,7 @@ Return a list of items where the filename is the `car' of each item and the
 #+header: :wrap "src emacs-lisp -n :eval never :tangle no"
 #+begin_src emacs-lisp -n :exports both :results value pp :tangle no
 (defun org-babel-active-languages ()
-  (let ((result '("conf" "text" "toml")))
+  (let (result)
     (mapatoms
      (lambda (x)
        (when (and
@@ -3297,15 +3292,10 @@ Return a list of items where the filename is the `car' of each item and the
 #+caption: Active Org Babel languages.
 #+RESULTS: lst:org-babel-active-languages
 #+begin_src emacs-lisp -n :eval never :tangle no
-(("C") ("C++") ("D") ("R") ("awk") ("calc") ("clojure")
+(("applescript") ("calc") ("conf") ("emacs-lisp") ("eshell")
- ("clojurescript") ("conf") ("cpp") ("css") ("ditaa") ("dot")
+ ("fortran") ("js") ("latex") ("latex-extra-header") ("latex-header")
- ("emacs-lisp") ("eshell") ("forth") ("fortran") ("gnuplot")
+ ("lisp") ("maxima") ("org") ("perl") ("python") ("racket") ("ruby")
- ("groovy") ("haskell") ("java") ("js") ("julia") ("latex")
+ ("scheme") ("shell") ("text") ("toml"))
- ("latex-extra-header") ("latex-header") ("lilypond") ("lisp") ("lua")
- ("makefile") ("matlab") ("maxima") ("ocaml") ("octave") ("org")
- ("perl") ("plantuml") ("processing") ("python") ("ruby") ("sass")
- ("scheme") ("screen") ("sed") ("shell") ("sql") ("sqlite") ("text")
- ("toml"))
 #+end_src
 
 *** [[https://github.com/bdarcus/citar][Citar: citing bibliography]] with [[https://orgmode.org/][Org Mode]]
@@ -3714,8 +3704,6 @@ See `org-link-parameters' for details about PATH, DESC and FORMAT."
            ("embark" . "https://github.com/oantolin/embark")
            ("magit" . "https://magit.vc/manual/magit.html")
            ("marginalia" . "https://github.com/minad/marginalia")
-           ("maxima" .
-            "https://maxima.sourceforge.io/docs/manual/maxima_singlepage.html")
            ("org" . "https://orgmode.org/org.html")
            ("orderless" . "https://github.com/oantolin/orderless")
            ("sly" . "https://joaotavora.github.io/sly/")
@@ -3955,12 +3943,11 @@ Load all test files first."
       ;; test-org-element/normalize-contents fails (can't fix).
       ;; test-ob-exp/noweb-on-export fails due to spacing (can't fix).
       ;; test-ob-exp/noweb-on-export-with-exports-results due to spacing (idem).
-      ;; ob-maxima fixed but spacing is fragile. Which Maxima?
       ;; ob-python hangs sometimes, but seldom.
       ;; ob-tangle/continued-code-blocks-w-noweb-ref fails.
       (ert (rx (or "org/" "org-fold" "org-element" "org-macro" "org-src"
                    "property-inheritance"
-                   "ob/" "ob-emacs-lisp" "ob-eshell" "ob-maxima"
+                   "ob/" "ob-emacs-lisp" "ob-eshell"
                    "ob-python" "ob-tangle")))
       (org-test-kill-all-examples)))
 
@@ -3975,10 +3962,10 @@ Load all test files first."
 
   (defun org-test-run-a-test-file ()
     "Run all tests in an Org test file (trailing `/' matters).
-Examples: `ob/' or `ob-maxima'."
+Examples: `ob/' or `ob-python'."
     (interactive)
     (let ((text (read-string "Org test file (without leading test-): "
-                             nil nil "ob-maxima")))
+                             nil nil "ob-python")))
       (org-test-load)
       (let (;; Catch errors in diary sexps better.
             (calendar-debug-sexp t))
@@ -6071,59 +6058,6 @@ byte code:
   (add-to-list 'auto-mode-alist `(,(rx ".go" eos) . go-ts-mode)))
 #+end_src
 
-** [[info:maxima#Top][Maxima Programming (info)]]
-:PROPERTIES:
-:CUSTOM_ID: sec:maxima-programming
-:END:
-
-Listing [[lst:configure-maxima]] configures the built-in =maxima= library. The
-following list contains more information:
-1. [[https://gitlab.com/sasanidas/maxima][Maxima Mode]] is an archived Emacs interface to the computer algebra system [[https://en.wikipedia.org/wiki/Maxima_(software)][Maxima]].
-2. [[https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-maxima.html][Maxima Source Code Blocks in Org Mode]] shows how to use [[https://en.wikipedia.org/wiki/Maxima_(software)][Maxima]] in [[https://orgmode.org/][Org Mode]].
-3. [[https://home.csulb.edu/~woollett/mbe.html][Maxima By Example]] is a tutorial for [[https://en.wikipedia.org/wiki/Maxima_(software)][Maxima]].
-Listing [[lst:maxima-example]] is a minimal example of how to use [[info:maxima#Top][Maxima (info)]] in
-[[https://orgmode.org/][Org Mode]] and it can work without the built-in =maxima= library or [[https://gitlab.com/sasanidas/maxima][Maxima Mode]].
-Enabling =maxima-mode= serves only to fontify the code.  See the =org-mode=
-mailing list message on the [[https://list.orgmode.org/87fs0geh47.fsf@t14.reltub.ca/][status of ob-maxima]] for a discussion of the header
-arguments of listing [[lst:maxima-example]].
-
-#+caption[Configure =maxima=]:
-#+caption: Configure =maxima=.
-#+name: lst:configure-maxima
-#+begin_src emacs-lisp -n :results silent
-(when (require 'maxima nil t)
-  ;; In case of https://gitlab.com/sasanidas/maxima, uncomment the next 2 lines:
-  ;; (add-hook 'maxima-mode-hook #'maxima-hook-function)
-  ;; (add-hook 'maxima-inferior-mode-hook #'maxima-hook-function)
-  (add-to-list 'auto-mode-alist
-               (cons "\\.mac\\'" 'maxima-mode))
-  (add-to-list 'interpreter-mode-alist
-               (cons "maxima" 'maxima-mode)))
-#+end_src
-
-#+caption[Maxima example]:
-#+caption: Maxima example.
-#+caption: The code is not fontified because =maxima-mode= is not enabled.
-#+header: :wrap "src text -n"
-#+name: lst:maxima-example
-#+begin_src maxima -n :batch batch :cmdline --quiet :exports both :results raw
-rat(1/(x+1) + x/(x-1));
-#+end_src
-
-#+caption[Maxima example results]:
-#+caption: Maxima example results.
-#+name: lst:maxima-example-results
-#+results: lst:maxima-example
-#+begin_src text -n
-(%i1) (linenum:0,
-(%i1) rat(1/(x+1)+x/(x-1))
-                                  2
-                                 x  + 2 x - 1
-(%o1)/R/                         ------------
-                                     2
-                                    x  - 1
-#+end_src
-
 ** [[https://www.seas.upenn.edu/~chaoliu/2017/09/01/python-programming-in-emacs/][Python programming]]
 :PROPERTIES:
 :CUSTOM_ID: sec:python-programming