this page:

https://orgmode.org/manual/Macro-Replacement.html#index-macro-replacement_002c-during-export

says:

Org also recognizes macro references in keywords, such as ‘CAPTION’, ‘TITLE’,
‘AUTHOR’, ‘DATE’, *and for some back-end specific export options.*

How do I discover what those back end specific options are?

Also, for various elements (e.g. begin_src emacs-lisp, begin_export html,
etc...) how do I discover what the acceptable keywords are, preferably
without only having to go thru the manual pages?

TIA,
-Kevin