A PAC file provides browser proxy-selection instructions and can be hosted either on a separate web server or directly on the Cisco Secure Web Appliance so client browsers can retrieve it and determine when to send traffic to the proxy.

After enabling HTTPS proxy, the appliance still needs identification profiles so traffic can be matched to users or client criteria, and an access/decryption policy so HTTPS traffic is handled according to the organization's inspection and control requirements.

The Cisco AVC engine provides granular application visibility and control, allowing the appliance to distinguish between different activities within the same social media site. This enables users to view social media content while blocking posting or other interactive actions.

https://www.cisco.com/c/en/us/support/docs/wireless-mobility/wlan-security/116052-config- webauth-proxy-00.html

Explanation:
HTTPS decryption requires the HTTPS proxy to be enabled first, followed by a certificate that the appliance can use for HTTPS inspection. Invalid certificate handling is then configured to define how certificate problems are treated, and Decrypt for Authentication is enabled so users can be authenticated during HTTPS transactions before policy enforcement continues.