I am tracking several issues with Summer '16 locker service in a pre-release org (on gs0) that are actively being discussed on this site. When Salesforce employee answers or comments with "a fix is scheduled for patch .2" or "this will be addressed with patch .5 scheduled to deploy next Tuesday" or similar comments, how can I tell what "patch" level my pre-release org is currently on? The "trust" and "Known Issues" sites that list release/patch details, do not list the gs0 pre-release instance.
At the time of this answer, you don't find out what patch they're on, at least not from a public resource. If you were a salesforce.com employee with access to the corporate network, you could access the internal network statistics pages, which is where they get their data from. All of this stuff is protected by an IP address filter, profile permissions, and so on. If you ask support nicely, they'll probably tell you, although without any public information to go on, the patch number is pretty meaningless to you directly.