* lisp/ox-org.el (org-org-publish-to-org):
* lisp/ox-html.el (org-html-htmlize-generate-css):
(org-html-fontify-code):
* lisp/org-agenda.el (org-agenda-write): Throw an error
requesting the user to install htmlize.el.
* doc/org.texi (Exporting agenda views, Literal examples):
Don’t assume htmlize.el is available.
You need to install it from https://github.com/hniksic/emacs-htmlize
See https://github.com/hniksic/emacs-htmlize/issues/7 for this issue.