Comments in Rise (not in Review)

Since I have older, current and in-progress versions of courses, I'd love to be able to provide myself and other content authors working on the project with comments on content, status, and so on. (What I have in mind is similar to programmers "commenting out" some text notes in their code.)

The comments need to be invisible in the published course but easily visible within Rise. Is this an existing or planned features? 

Thanks