Is the winmain lab obsolete or deprecated? (Windows 10)

[AS95678]

According to BuildFeed, the last known compile by the winmain lab was a version of the Windows 10 RTM build. Since then there hasn't been a peep from winmain on BuildFeed, not even any documentation or anything. Has winmain been deprecated since Windows 10 went to RTM? If they are, which branch will serve as the main branch to reverse integrate into and serve as winmain's replacement?

[WILSON2bGg]

I don’t know what happened but my best guesses are that they are working on something major or that the lab was shutdown due to the insider program

[MrBurgerKing]

I bet it has something to do with the shift to SaaS. Server 2019 skipped rtm entirely!
From buildfeed it looks like development is done internally, pushed to rs_prelease for insider testing, then every new major 'update' to 10 get's its own branch.

[kw259]

Well, there's always the rsmain branch, which appears to act as winmain but exclusively for Redstone rather than Windows development as a whole.