AWS WAF is a managed web application firewall that monitors network traffic to AWS applications and resources, providing perimeter-based security. It generates standard request metrics, CAPTCHA and challenge metrics, and bot control metrics to help monitor its performance and identify potential issues. Activity logs capture information about requests processed by web ACLs, while audit logs record any activity associated with user updates or access to web ACLs. Monitoring these logs can provide valuable insights into AWS WAF's efficiency and help ensure application security.