> SETUPFILE exports keywords defined in `org-export-options-alist' and in back-end
specific options (i.e. :options-alist).

I tried "C-h v org-export-options-alist" but the result seemed cryptic to
me:

((:title "TITLE" nil nil parse) (:date "DATE" nil nil parse) (:author
 "AUTHOR" nil user-full-name parse) (:email "EMAIL" nil
 user-mail-address t) (:language "LANGUAGE" nil
 org-export-default-language t) (:select-tags "SELECT_TAGS" nil
 org-export-select-tags split) (:exclude-tags "EXCLUDE_TAGS" nil
 org-export-exclude-tags split) (:creator "CREATOR" nil
 org-export-creator-string) (:headline-levels nil "H"
 org-export-headline-levels) (:preserve-breaks nil "\\n"
 org-export-preserve-breaks) (:section-numbers nil "num"
 org-export-with-section-numbers) (:time-stamp-file nil "timestamp"
 org-export-time-stamp-file) (:with-archived-trees nil "arch"
 org-export-with-archived-trees) (:with-author nil "author"
 org-export-with-author) (:with-broken-links nil "broken-links"
 org-export-with-broken-links) (:with-clocks nil "c"
...

> For example, in latex back-end the latter category is
>   LATEX_CLASS, LATEX_CLASS_OPTIONS, LATEX_HEADER, LATEX_HEADER_EXTRA,
>   DESCRIPTION, KEYWORDS, SUBTITLE, LATEX_COMPILER, DATE

That helps. Thanks!