Hello Luigi,
What you say is right.
"Undisclosed" does not seem to appear in MoodleDocs or in the Tracker.
MoodleDocs does not mention that aliases cannot be used in quizzes, except with the Essay question type. (https://docs.moodle.org/38/en/Working_with_files#Areas_in_which_aliases_cannot_be_made)
So, my feeling is that it shouldn't be a problem, but you should really check it out for yourself. Having the actual link to the quiz rather than the word "undisclosed" should be considered an improvement for which you could open a Tracker issue.
What you say is right.
"Undisclosed" does not seem to appear in MoodleDocs or in the Tracker.
MoodleDocs does not mention that aliases cannot be used in quizzes, except with the Essay question type. (https://docs.moodle.org/38/en/Working_with_files#Areas_in_which_aliases_cannot_be_made)
So, my feeling is that it shouldn't be a problem, but you should really check it out for yourself. Having the actual link to the quiz rather than the word "undisclosed" should be considered an improvement for which you could open a Tracker issue.