ox-org: Export special table rows by default

* lisp/ox.el (org-export-options-alist): New internal plist option -
:with-special-rows.  Defaults to nil.
(org-export--skip-p): Do not skip special table rows when
:with-special-rows is non-nil.
* lisp/ox-org.el (org-org-with-special-rows): New custom option
controlling whether to export special table rows.  t by default.
(org): Use `org-org-with-special-rows' as the value of
:with-special-rows option.
* etc/ORG-NEWS (=ox-org= now exports special table rows by default):
(New option ~org-org-with-special-rows~): Announce the change.

etc/ORG-NEWS

@@ -13,6 +13,13 @@ Please send Org bug reports to mailto:emacs-orgmode@gnu.org.
 
 * Version 9.7 (not released yet)
 ** Important announcements and breaking changes
+*** =ox-org= now exports special table rows by default
+
+Previously, when exporting to Org, special table rows (for example,
+width cookies) were not exported.   Now, they are exported by default.
+
+You can customize new option ~org-org-with-special-rows~ to fall back to previous behavior.
+
 *** Org babel backends are now expected to define an additional API function ~org-babel-session-buffer:<lang>~
 
 Org babel now uses session buffer (if it exists) to retrieve
@@ -501,6 +508,11 @@ The change is breaking when ~org-use-property-inheritance~ is set to ~t~.
 
 The =TEST= parameter is better served by Emacs debugging tools.
 ** New and changed options
+*** New option ~org-org-with-special-rows~
+
+The new options controls whether to export special table rows in
+Org-Org (=ox-org=) export.  The default value is ~t~.
+
 *** New option ~org-babel-comint-fallback-regexp-threshold~
 
 Org babel is often using Emacs' interactive REPL feature to implement

lisp/ox-org.el

@@ -54,6 +54,11 @@ setting of `org-html-htmlize-output-type' is `css'."
 	  (const :tag "Don't include external stylesheet link" nil)
 	  (string :tag "URL or local href")))
 
+(defcustom org-org-with-special-rows t
+  "Non-nil means export special table rows.
+Special rows are the rows containing special marking characters, as
+described in the Info node `(org)Advanced features'.")
+
 (org-export-define-backend 'org
   '((babel-call . org-org-identity)
     (bold . org-org-identity)
@@ -112,7 +117,10 @@ setting of `org-html-htmlize-output-type' is `css'."
 	    (lambda (a s v b)
 	      (if a (org-org-export-to-org t s v b)
 		(org-open-file (org-org-export-to-org nil s v b)))))))
-  :filters-alist '((:filter-parse-tree . org-org--add-missing-sections)))
+  :filters-alist '((:filter-parse-tree . org-org--add-missing-sections))
+  :options-alist
+  ;; Export special table rows.
+  '((:with-special-rows nil nil org-org-with-special-rows)))
 
 (defun org-org--add-missing-sections (tree _backend _info)
   "Ensure each headline has an associated section.

lisp/ox.el

@@ -140,6 +140,7 @@
     (:with-properties nil "prop" org-export-with-properties)
     (:with-smart-quotes nil "'" org-export-with-smart-quotes)
     (:with-special-strings nil "-" org-export-with-special-strings)
+    (:with-special-rows nil nil nil)
     (:with-statistics-cookies nil "stat" org-export-with-statistics-cookies)
     (:with-sub-superscript nil "^" org-export-with-sub-superscripts)
     (:with-toc nil "toc" org-export-with-toc)
@@ -1838,7 +1839,9 @@ not exported."
      (and (org-export-table-has-special-column-p
 	   (org-element-lineage datum 'table))
 	  (org-export-first-sibling-p datum options)))
-    (table-row (org-export-table-row-is-special-p datum options))
+    (table-row
+     (unless (plist-get options :with-special-rows)
+       (org-export-table-row-is-special-p datum options)))
     (timestamp
      ;; `:with-timestamps' only applies to isolated timestamps
      ;; objects, i.e. timestamp objects in a paragraph containing only