The Policy Optimizer feature enables an administrator to review the Security policy rule base for unused rules, unused applications, and shadowed rules. The Policy Optimizer provides information and recommendations to help optimize the Security policy rules and reduce the attack surface. The Policy Optimizer can also identify rules that can be converted to use App-ID instead of port-based criteria12. Reference: Policy Optimizer, Tips & Tricks: How to Identify Unused Policies on a Palo Alto Networks Device