I am writing this interface to my university's learning management system: https://github.com/titaniumbones/Org-Marking-Mode/tree/use-structured-course-def. I am only using hte exporting system tangentially and I have not defined a new exporter. However, I would really like to be able to set some variable values in the header section of hte document, e.g.:

#+ORG_LMS_COURSE: becomingmodern

or

#+PROPERTY: org-lms-course hackinghistory

I thought the latter might work but (org-entry-get-with-inheritance "org-lms-course) and (org-entry-get-with-inheritance "ORG_LMS_COURSE") both return nil.  The former is in any case somewhat cleaner-looking but I am not finding in the manual an instructions on how to add my own keywords.  Is it possible to do this? I can of course always set a buffer-local variable in a src block, e.g.:

#+begin_src emacs-lisp

(setq org-lms-course 'becomingmodern)

#+end_src.

but I would like to be able to avoid that where possible.

Thanks for the help as usual!