Q: What cookies do you store in Silo and in Toolbox? 

A: The virtual Silo and Toolbox browsers behave like a traditional browsers while a given session is running.  For example, if you were to log into amazon.com during a Silo session and then you clicked on a link for Amazon in a separate Silo tab, your cookie indicating you were logged into amazon would be present in the second link that you opened.  This is true of Silo and Toolbox.  This cookie behavior does not extend across open Toolbox instances, however.  For example, if you have two separate Toolbox windows open, the cookie containers are distinct. 

Once a session is closed, Toolbox and Silo behave differently.  For Toolbox sessions, nothing is ever saved so all cookies are purged and a fresh browser is presented to the user upon launch.  This is mostly true for Silo except for users who choose to save their logins in a web app and have Credential Saving Control set to Enabled (about Credential Saving Control).  In addition to credentials, we often will save relevant cookies to prevent MFA logins from appearing and for other usability reasons.  What we save varies from site to site.