Build: 13S5255d
Updated: Jun 23, 2015
Requires: iOS 9 beta
For those who had previously installed watchOS 2 beta Configuration Profile (for watchOS beta 1 from June 8, 2015), you will get watchOS 2 beta 2 and the subsequent betas as the become available.
It is similar to OS X (insert codename here) Configuration Utility. Once you had it installed, you will automatically notified of the new builds.
For those who have not installed iOS 9 beta and watchOS beta, proceed with cautions. Ask yourself why you want the beta software on your devices.
If you chose to do so, please be aware that you would encounter many bugs that might render your device seemingly useless. You "could" try restoring your devices to the current release version. Other than that you had to weather the bug swarms until the next build is released.
Hope that helps.