If you have offices or datacenters in timezones different from your account timezone, you can display a list of those timezones to easily reference the time differences between the zones.
These are set at the account level, on the Account Profile page. To view them, click the account timezone (with the clock icon) in the site header on any page, and they will be shown in the left sidebar. They are sticky, so they will remain showing in your current browser on every page until you hide them again.