The 'myoverview' ('/blocks/myoverview') block records the user preference for the state of its tabs.  For example in lib.php there is:

````

function block_myoverview_user_preferences() {
$preferences = array();
$preferences['block_myoverview_last_tab'] = array(
'type' => PARAM_ALPHA,
'null' => NULL_NOT_ALLOWED,
'default' => BLOCK_MYOVERVIEW_TIMELINE_VIEW,
'choices' => array(BLOCK_MYOVERVIEW_TIMELINE_VIEW, BLOCK_MYOVERVIEW_COURSES_VIEW)
);

return $preferences;
}

````

being the user preference 'block_myoverview_last_tab'.  However in 'classes/privacy/provider.php' the 'null_provider' class is implemented 'class provider implements \core_privacy\local\metadata\null_provider' indicating that no user data is stored.  This is clearly not the case.  The language file states 'The Course overview block only shows data stored in other locations.' but it stores a user preference pertaining to a user id.