You will not find anything. F5 doesnt care... since passive mode is where the server and client interact with cookies and the normal timeout/expiration is evaluated by the server when a cookie is presented back on subsequent connections.
- HTTP Cookie PassiveUsing the HTTP Cookie Passive method is unlike the other cookie persistence methods. The BIG-IP system does not insert or search for blank Set-Cookie headers in the response from the server. This method does not try to set up the cookie. With this method, the server provides the cookie, formatted with the correct server information and timeout.