Recently upgraded to version 2.3.5 by GIT.
Previously, completed quizzes provided reports including an item analysis for individual questions. This used to be accessed via a link under results > statistics. Now that link is gone and results > grades is all that is left. Not even an admin user can view the statistics.
EDIT: Statistics can be accessed by users with permissions mod/quiz:viewreports and quiz/statistics:view enabled by editing the URI manually (changing ...mode=overview to ...mode=statistics) however no links are present in the navigation block.