Here's the Atronix announcement - http://rebol.info/altme/105/announce#msg0688
I believe you can consider this as the official build for Rebol3 View/GUI because Saphiron took over the RebGUI/R3-GUI project from Rebol Technologies.
But yes some of the Rebol 3 Core stuff that Saphiron/Altronix have done do need merging back into main open source core [1], which itself as moved on from the Saphir codebase (Saphiron Rebol build) [2].
[1] - https://github.com/rebol/rebol
[2] - https://github.com/saphirion/saphir
Also see Rebolsource repo where lot of the community changes go before merging back into [1]. Ref: https://github.com/rebolsource/r3 | http://www.rebolsource.net
PS. I know that you're aware of some of this info. Posting for the eyeballs of others :)
Edit: It looks like that is Saphiron's repo, not the main one, so still waiting on it becoming an official build, I see :-P