Apple just posted information about how to sign apps to work with Gatekeeper: https://developer.apple.com/resources/developer-id/ Any idea when we might see a version of GIMP for Mac that is signed with a Developer ID?
Unlikely as far as I know. The Gimp developers primarily develop Gimp on the Linux platform and don't provide an official binary for Mac. So unless there's a 3rd party willing to fork over the $$$ for an apple developer certificate, cross compile, and then sign it then this won't happen.
... well, as I'm a registered as an Apple developer, it's likely that I can get the GIMP on OS X packages signed with my Dev ID. (I just had no time to dive more into this code signing....) -skl