The org mode manual says "The project property list is scoped into this
call as the variable project-plist". But, ox-publish.el has lexical
binding enabled, and the variable project-plist doesn't seem to be
accessible from the executed preparation-function. When I try to access
the variable, I get a (void-variable project-plist) error.

Please find attached a minimal elisp file to reproduce the bug.

emacs -Q -l preparation-function-dynamic-scoping.el

My understanding of dynamic and lexical binding is a little foggy. So,
do let me know if I'm missing something.

Regards,
Arun Isaac.