export: Remove `org-export-special-keywords'

* lisp/ox.el (org-export-special-keywords):
(org-export--get-inbuffer-options): Do not use `org-export-special-keywords'.

etc/ORG-NEWS

@@ -303,7 +303,11 @@ Use ~org-hide-block-toggle~ instead.
 This function was not used in the code base, and has no clear use
 either.  It has been marked for future removal.  Please contact the
 mailing list if you use this function.
-*** Removed  ~org-maybe-keyword-time-regexp~
+*** Removed ~org-maybe-keyword-time-regexp~
+
+The variable was not used in the code base.
+
+*** Removed ~org-export-special-keywords~
 
 The variable was not used in the code base.
 

lisp/ox.el

@@ -172,12 +172,6 @@ All these properties should be back-end agnostic.  Back-end
 specific properties are set through `org-export-define-backend'.
 Properties redefined there have precedence over these.")
 
-(defconst org-export-special-keywords '("FILETAGS" "SETUPFILE" "OPTIONS")
-  "List of in-buffer keywords that require special treatment.
-These keywords are not directly associated to a property.  The
-way they are handled must be hard-coded into
-`org-export--get-inbuffer-options' function.")
-
 (defconst org-export-filters-alist
   '((:filter-body . org-export-filter-body-functions)
     (:filter-bold . org-export-filter-bold-functions)
@@ -1485,7 +1479,7 @@ Assume buffer is in Org mode.  Narrowing, if any, is ignored."
       ;; Read options in the current buffer and return value.
       (dolist (entry (org-collect-keywords
 		      (nconc (delq nil (mapcar #'cadr options))
-			     org-export-special-keywords)))
+			     '("FILETAGS" "OPTIONS"))))
 	(pcase entry
 	  (`("OPTIONS" . ,values)
 	   (setq plist