Use private files in lessons?

Problem/Motivation

I would like to add private files for students to download in my lessons, but the only option that shows up is the public files. Is there a way to choose files from the site's private directory?

Proposed resolution

Is there a way to do this? If there is not, can it be added please?

Remaining tasks

User interface changes

Option to use / choose from private files.

API changes

Data model changes