in src/main/java/org/apache/sling/starter/access/models/PrivilegeItem.java [172:177]
    public void addDenyRestrictionToDelete(String restrictionName) {
        if (denyRestrictionsToDelete == null) {
            denyRestrictionsToDelete = new HashSet<>();
        }
        denyRestrictionsToDelete.add(restrictionName);
    }