'Implicitly Uses' has web-browsing listed. This means that if you allow facebook-posting, that it will also be allowing the web-browsing application implicitly.. In our case, we dont know which APP the question referes too but 'Implicitly means already uses HTTP.

https://docs.paloaltonetworks.com/pan-os/10-1/pan-os-admin/user-id/user-id-concepts/user-mapping/globalprotect.html GlobalProtect is a VPN solution that provides secure remote access to corporate networks. When a user connects to GlobalProtect, their identity is verified against an LDAP server. This ensures that all IP address-to-user mappings are explicitly known.

https://docs.paloaltonetworks.com/pan-os/9-1/pan-os-new-features/user-id-features/dynamic-user-groups Use the dynamic user group in a policy to regulate traffic for the members of the group. You will need to configure at least two rules: one to allow initial traffic to populate the dynamic user group and one to deny traffic for the activity you want to prevent (in this case, questionable-activity). To tag users, the rule to allow traffic must have a higher rule number in your rulebase than the rule that denies traffic.
https://docs.paloaltonetworks.com/pan-os/10-2/pan-os-admin/policy/use-dynamic-user-groups-in-policy