the easiest way would be to disable the timer
remove all non favorites
login to xmarks (or open it - im not sure if its an extension or not?)
then see which new cookies are stored in Cookie - and select them as favorites

there may also be tracking cookies, if there are any RED coloured cookies included in the favourite:

you will also need to whitelist that you do that by selecting the RED cookie, and right-clicking (control-click) * to bring up the contextual menu then select "Add to Whitelist"