Direct access via web browser requires authentication is the restriction that is in place for end users accessing the spam quarantine on Cisco Secure Email Gateway appliances. Spam quarantine is a feature that allows Cisco ESA to store messages that are suspected to be spam and allow end users or administrators to review them and release or delete them as needed.
End users can access their personal spam quarantine on Cisco ESA either by clicking on a link in a notification email or by entering their email address and password in a web browser. In both cases, authentication is required to ensure security and privacy.
The other options are not valid restrictions that are in place for end users accessing the spam quarantine on Cisco Secure Email Gateway appliances, because they are either not mandatory or not related to authentication.

The PVO cannot be enabled and shows this type of error message.
Unable to proceed with Centralized Policy, Virus and Outbreak Quarantines configuration as host1 and host2 in Cluster have content filters / DLP actions available at a level different from the cluster Level.
The error message can indicate that one of the hosts does not have a DLP feature key applied and DLP is disabled. The solution is to add the missing feature key and apply DLP settings identical as on the host that has the feature key applied. This feature key inconsistency might have the same effect with Outbreak Filters, Sophos Antivirus, and other feature keys.
https://www.cisco.com/c/en/us/support/docs/security/email-security-appliance/118026-technote-esa-00.html

The default behavior of any listener for TLS communication is B. off. This means that TLS is not allowed for incoming connections to the listener and connections to the listener do not require encrypted Simple Mail Transfer Protocol (SMTP) conversations. This is stated in the web search result 1. To enable TLS for a listener, you need to configure the Use TLS option in the mail flow policy settings for the listener on the Mail Policies > HAT Overview page1. You can choose from three different settings for TLS: No, Preferred, or Required1.

Explanation/Reference: https://www.cisco.com/c/en/us/td/docs/security/esa/esa11-1/user_guide/ b_ESA_Admin_Guide_11_1/b_ESA_Admin_Guide_chapter_01000.html#con_1133810

Modify Subject is an additional option that should be used to help the end users be aware of the elevated risk of interacting with these messages. Modify Subject allows the administrator to add a prefix or suffix to the message subject, such as "[SPF Fail]", to indicate that the message has failed the SPF verification and may be fraudulent or spoofed.
The other options are not valid additional options to help the end users be aware of the elevated risk of interacting with these messages, because they do not affect the message subject or provide any warning to the end users.