You are in the developer but would like to test the OS X Yosemite 10.10.3, which brings the brand new Photos app, new Emojis and a new integration with Google's login screens (making things easier for those who have 2-step verification enabled on their account)? For your turn has come!
Apple has now released a public test version of 10.10.3 (build 14D87p) in OS X Beta Program if you are already part of the program, the update is most likely available in the Software Update (built into the Mac App Store). As we can see, little has changed in this version compared to the last one made available to developers last week (compilation 14D87h).
Those who are not yet part of the program can register here.